[VOL-5051] - Triage bbsim build

[VOL-5092] - verify_bbsim_unit-test repository failures in jenkins job history.

makefiles/*
-----------
  o Merge in latest library makefiles.
  o Some legacy retained:
      tools.mk => makefiles/docker/include.mk
      makefiles/lint/docker/*.mk (replace with docker/include.mk.new)

Makefile
--------
  o Remove bogus foobar target.
  o Target docs-lint now maps to library target lint-doc8.

docs/Makefile
-------------
  o venv install now handled by makefiles/virtualenv.mk
  o Replaced inlined doc8 lint target with makefiles/lint/doc8 (lint-doc8)
  o Use std defines for SHELL= and other constants.
  o Replace separator ';' with '&&' in commands using venv (detect errors).

config.mk
---------
  o Enable lint targets for doc8, docker & json.
  o More lint checks can be enabled but cleanup is needed first.

docs/Makefile
requirements.txt
----------------
  o Identified a few python module problems documented in VOL-5092.
  o Makefile wild target(%) matching stray dependencies so hardcode sphinx targets to act on.
  o Added hyphen/success to "make docs" until VOL-5092 can be straightened out.

Change-Id: Ibe4006747ee610bfe8ac0fdbb339e5e18e6e9176
diff --git a/makefiles/consts.mk b/makefiles/consts.mk
index 941df38..f1f717f 100644
--- a/makefiles/consts.mk
+++ b/makefiles/consts.mk
@@ -17,6 +17,7 @@
 # SPDX-FileCopyrightText: 2022-2023 Open Networking Foundation (ONF) and the ONF Contributors
 # SPDX-License-Identifier: Apache-2.0
 # -----------------------------------------------------------------------
+# https://gerrit.opencord.org/plugins/gitiles/onf-make
 # ONF.makefile.version = 1.0
 # -----------------------------------------------------------------------
 
@@ -26,15 +27,26 @@
 export dot          :=.
 export null         :=#
 export space        := $(null) $(null)
-export quote-single := $(null)'$(null)# colorization-closing-quote(')
-export quote-double := $(null)"$(null)# colorization-closing-quote(")
+export quote-single := $(null)'$(null)#'
+export quote-double := $(null)"$(null)#"
 
 # [DEBUG] make {target} HIDE=
-HIDE        ?= @
+HIDE           ?= @
 
 env-clean      ?= /usr/bin/env --ignore-environment
-xargs-n1       := xargs -0 -t -n1 --no-run-if-empty
-xargs-n1-clean := $(env-clean) $(xargs-n1)
+
+xargs-cmd       := xargs -0 -t --no-run-if-empty
+xargs-n1        := $(xargs-cmd) -n1
+xargs-n1-clean  := $(env-clean) $(xargs-n1)
+xargs-cmd-clean := $(env-clean) $(xargs-cmd)
+
+## -----------------------------------------------------------------------
+## Intent: NOP command for targets whose dependencies do all heavy lifting
+## -----------------------------------------------------------------------
+## usage: foo bar tans
+## <tab>$(nop-command)
+## -----------------------------------------------------------------------
+nop-cmd        := :
 
 ## -----------------------------------------------------------------------
 ## Default shell: