Integration edits for repo:voltha-docs use.

This patch will add makefile targets and exclusions for doc8 (estructuredText) linting.

makefiles/lint/doc8/excl.mk
makefiles/lint/doc8/doc8.mk
makefiles/lint/doc8/help.mk
makefiles/lint/doc8/include.mk
makefiles/lint/doc8/install.mk
------------------------------
  o Apply exclusion list so checking will not fail on python venv dirs.
  o Split include.mk into named modular makfiles.

makefiles/lint/include.mk
makefiles/lint/shell.mk
-------------------------
  o Remove legacy shell.mk config, lint target loads from lint/shell/*.

Change-Id: I8c214dc499356edf9778ae7ec1deeddf35bd3b65
diff --git a/makefiles/lint/doc8/doc8.mk b/makefiles/lint/doc8/doc8.mk
new file mode 100644
index 0000000..04101fe
--- /dev/null
+++ b/makefiles/lint/doc8/doc8.mk
@@ -0,0 +1,59 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2017-2022 Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# -----------------------------------------------------------------------
+
+##-------------------##
+##---]  GLOBALS  [---##
+##-------------------##
+.PHONY: lint-doc8 lint-doc8-all lint-doc8-modified
+
+have-doc8-files := $(if $(strip $(DOC8_SOURCE)),true)
+DOC8_SOURCE     ?= $(error DOC8_SOURCE= is required)
+
+# -----------------------------------------------------------------------
+# Well that is annoying.  Cannot pass two --config switches, doc8 will
+# use only one.  Repos have more special exclusions so pass onf-make
+# doc8 config as command line args so local makefiles to use --config
+# -----------------------------------------------------------------------
+# lint-doc8-args += --config $(ONF_MAKEDIR)/lint/doc8/doc8.ini
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+ifndef NO-LINT-DOC8
+  lint-doc8-mode := $(if $(have-doc8-files),mod,all)
+  lint : lint-doc8-$(lint-doc8-mode)
+endif# NO-LINT-DOC8
+
+## -----------------------------------------------------------------------
+# Support consistent lint target names across makefiles
+# Clone logic makefiles/lint/shellcheck/shellcheck.mk deps
+# *-{mod, src} targets and exclusiosn.
+## -----------------------------------------------------------------------
+lint-doc8-all : lint-doc8
+lint-doc8-mod : lint-doc8
+lint-doc8-src : lint-doc8
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+## [TODO] - move lint-doc8-excl into doc8.ini
+lint-doc8-excl := $(foreach dir,$(onf-excl-dirs) $(lint-doc8-excl),--ignore-path "$(dir)")
+lint-doc8: lint-doc8-cmd-version
+
+	$(call banner-enter,Target $@)
+	$(activate) && doc8 $(lint-doc8-excl) $(lint-doc8-args)
+	$(call banner-enter,Target $@)
+
+# [EOF]
diff --git a/makefiles/lint/doc8/excl.mk b/makefiles/lint/doc8/excl.mk
index efa71da..65bf3fa 100644
--- a/makefiles/lint/doc8/excl.mk
+++ b/makefiles/lint/doc8/excl.mk
@@ -20,21 +20,31 @@
 ## -----------------------------------------------------------------------
 ## -----------------------------------------------------------------------
 
-## excl := $(wildcar */*/.git)
+lint-doc8-excl-raw += '*/.git'
 lint-doc8-excl-raw += '$(venv-name)'
 lint-doc8-excl-raw += '*/$(venv-name)'
+
+# Should we filter generated content as redundant ?
+# Considering _build will be published and consumed.
 $(if $(BUILDDIR),\
   $(excl lint-doc8-excl-raw += '$(BUILDDIR)'))
 
+# -----------------------------------------------------------------------
 # YUCK! -- overhead
 #   o Submodule(s) use individual/variant virtualenv install paths.
 #   o Exclude special snowflakes to enable library makefile use.
 #   o All can use virtualenv.mk for consistent names and cleanup
 #   o [TODO] Ignore submodules, individual repos should check their sources.
+# -----------------------------------------------------------------------
+lint-doc8-excl-raw += '*/venv_*'#   # '*/venv_cord'
+lint-doc8-excl-raw += '*/*_cord'#   # '*/vst_venv'
 
-lint-doc8-excl-raw += '*/venv_cord'
-lint-doc8-excl-raw += '*/vst_venv'
-
+## -----------------------------------------------------------------------
+## repo:voltha-docs exclusions
+## Migrate into one of:
+##   makefiles/local/lint/doc8/doc8.ini
+##   makefiles/local/lint/doc8/excl.mk
+## -----------------------------------------------------------------------
 lint-doc8-excl-raw += './cord-tester'
 lint-doc8-excl-raw += './repos/cord-tester'
 
diff --git a/makefiles/lint/doc8/help.mk b/makefiles/lint/doc8/help.mk
new file mode 100644
index 0000000..1ec6cb8
--- /dev/null
+++ b/makefiles/lint/doc8/help.mk
@@ -0,0 +1,46 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2022-2023 Open Networking Foundation (ONF) and the ONF Contributors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# -----------------------------------------------------------------------
+
+$(if $(DEBUG),$(warning ENTER))
+
+## -----------------------------------------------------------------------
+## Intent: Display topic help
+## -----------------------------------------------------------------------
+help-summary ::
+	@printf '  %-30s %s\n' 'lint-doc8'\
+      'Style check ReStructed Text (rst) documents'
+	@printf '  %-30s %s\n' 'lint-doc8-help'\
+	  'Show verbose target help'
+  ifdef VERBOSE
+	@$(MAKE) --no-print-directory lint-doc8-help
+  endif
+
+## -----------------------------------------------------------------------
+## Intent: Display extended topic help
+## -----------------------------------------------------------------------
+.PHONY: lint-doc8-help
+lint-doc8-help ::
+	@printf '  %-30s %s\n' 'lint-doc8-all'\
+	  'Doc8 check available sources'
+	@printf '  %-30s %s\n' 'lint-doc8-mod'\
+	  'Doc8 check locally modified files (git status)'
+#	@printf '  %-30s %s\n' 'lint-doc8-src'\
+#	  'Doc8 check files by path'
+
+$(if $(DEBUG),$(warning LEAVE))
+
+# [EOF]
diff --git a/makefiles/lint/doc8/include.mk b/makefiles/lint/doc8/include.mk
index 22a24fa..564fca9 100644
--- a/makefiles/lint/doc8/include.mk
+++ b/makefiles/lint/doc8/include.mk
@@ -15,59 +15,12 @@
 # limitations under the License.
 # -----------------------------------------------------------------------
 
-##-------------------##
-##---]  GLOBALS  [---##
-##-------------------##
-.PHONY: lint-doc8 lint-doc8-all lint-doc8-modified
-
-have-doc8-files := $(if $(strip $(DOC8_SOURCE)),true)
-DOC8_SOURCE     ?= $(error DOC8_SOURCE= is required)
-
 ##--------------------##
 ##---]  INCLUDES  [---##
 ##--------------------##
-# include $(ONF_MAKEDIR)/lint/doc8/help.mk
+include $(ONF_MAKEDIR)/lint/doc8/doc8.mk
+include $(ONF_MAKEDIR)/lint/doc8/excl.mk
+include $(ONF_MAKEDIR)/lint/doc8/help.mk
 include $(ONF_MAKEDIR)/lint/doc8/install.mk
 
-# -----------------------------------------------------------------------
-# Well that is annoying.  Cannot pass two --config switches, doc8 will
-# use only one.  Repos have more special exclusions so pass onf-make
-# doc8 config as command line args so local makefiles to use --config
-# -----------------------------------------------------------------------
-# lint-doc8-args += --config $(ONF_MAKEDIR)/lint/doc8/doc8.ini
-
-## -----------------------------------------------------------------------
-## -----------------------------------------------------------------------
-ifndef NO-LINT-DOC8
-  lint-doc8-mode := $(if $(have-doc8-files),modified,all)
-  lint : lint-doc8-$(lint-doc8-mode)
-endif# NO-LINT-DOC8
-
-# Consistent targets across lint makefiles
-lint-doc8-all      : lint-doc8
-lint-doc8-modified : lint-doc8
-
-## -----------------------------------------------------------------------
-## -----------------------------------------------------------------------
-## [TODO] - move lint-doc8-excl into doc8.ini
-# lint-doc8-excl := $(foreach dir,$(onf-excl-dirs) $(lint-doc8-excl),--ignore-path "$(dir)")
-lint-doc8-excl := $(null)
-lint-doc8: lint-doc8-cmd-version
-
-	$(call banner-enter,Target $@)
-	$(activate) && doc8 --version
-	@echo
-	$(activate) && doc8 $(lint-doc8-excl) $(lint-doc8-args)
-	$(call banner-enter,Target $@)
-
-## -----------------------------------------------------------------------
-## Intent: Display command usage
-## -----------------------------------------------------------------------
-help::
-	@echo '  lint-doc8          Syntax check python using the doc8 command'
-  ifdef VERBOSE
-	@echo '  lint-doc8-all       doc8 checking: exhaustive'
-	@echo '  lint-doc8-modified  doc8 checking: only modified'
-  endif
-
 # [EOF]