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/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'