[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/lint/robot.mk b/makefiles/lint/robot.mk
index 9808602..369dfa8 100644
--- a/makefiles/lint/robot.mk
+++ b/makefiles/lint/robot.mk
@@ -30,10 +30,8 @@
 
 lint : lint-robot
 
-lint-robot: vst_venv
-	source ./$</bin/activate \
-	    && set -u \
-	    && rflint $(LINT_ARGS) $(ROBOT_FILES)
+lint-robot: $(venv-activate-script)
+	$(activate) && rflint $(LINT_ARGS) $(ROBOT_FILES)
 
 help::
 	@echo "  lint-robot           Syntax check robot sources using rflint"