Makefile library merge with onf-make and voltha-lib-go

makefiles/
----------
  o Import standalone makefile directories to checkin smaller parts of a mega patch.
  o Build out directory hierarchy by topic and feature.

makefiles/lint/yaml/
--------------------
  o Pull in logic evolved in repo:voltha-lib-go.
  o Refactoring: support special snowflake targets by repository.
  o ci-management and voltha-lib-go use distinct yamllint.conf files.
  o Separate until there is time to review and consolidate.
  o Added deps for on-demand local install of yamllint.
    - requirements.txt could be used but every build would incur overhead.

Makefile
--------
  o Use latest syntax from repo:onf-make.
  o No need to set path variables, makefiles/include.mk can infer them.
  o Added a help target to explicitly display targets and suggestions.
  o Logic is bundled in libraries and use of 'make help' is not well known.

Change-Id: Id8eba6f914a7bfe9a31637901bd8fb78a387e0c2
diff --git a/makefiles/lint/yaml/byrepo/voltha-lib-go/todo b/makefiles/lint/yaml/byrepo/voltha-lib-go/todo
new file mode 100644
index 0000000..8400c64
--- /dev/null
+++ b/makefiles/lint/yaml/byrepo/voltha-lib-go/todo
@@ -0,0 +1,39 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2022-2023 Open Networking Foundation (ONF) and the ONF Contributors
+# -----------------------------------------------------------------------
+
+##-------------------##
+##---]  GLOBALS  [---##
+##-------------------##
+env-clean = /usr/bin/env --ignore-environment
+xargs-n1      := xargs -0 -t -n1 --no-run-if-empty
+
+yamllint      := $(env-clean) $(YAMLLINT)
+yamllint-args := -c .yamllint
+
+##-------------------##
+##---]  TARGETS  [---##
+##-------------------##
+lint : lint-yaml
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+lint-yaml:
+	$(HIDE)$(env-clean) find . -name '*.yaml' -type f -print0 \
+	    | $(xargs-n1) $(yamllint) $(yamllint-args)
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+help:
+	@echo
+	@echo "USAGE: $(MAKE)"
+	@echo "  lint        perform syntax checks on source"
+	@echo "  test        perform syntax checks on source"
+	@echo "  pre-check   Verify tools and deps are available for testing"
+	@echo
+	@echo "[LINT]"
+	@echo "  lint-json   Syntax check .json sources"
+	@echo "  lint-yaml   Syntax check .yaml sources"
+	@echo
+# [EOF]