[VOL-5297] Add more pre-commit hooks and git submodule install helpers.

makefiles/consts.mk
-------------------
  o Define macro $(comma) for use in rules (helps avoid delimiter problems).

install/include.mk
install/README.md
------------------
  o Common files installed by bin/setup.sh.
  o Copy into a repositry when repo:onf-make is added as a git submodule.

.pre-commit-config.yaml
-----------------------
  o Include more pre-commit hooks for checking.
  o Added in voltha-lib-go, voltha-docs and others.
  o Include here for central mgmt.

[HOWTO: test]
% make venv
% source .venv/bin/activate
% pre-commit

Change-Id: I15bb814b7d75a450d34af448cb88344d3922c907
Signed-off-by: Joey Armstrong <jarmstrong@linuxfoundation.org>
diff --git a/makefiles/consts.mk b/makefiles/consts.mk
index 7bb882d..6670254 100644
--- a/makefiles/consts.mk
+++ b/makefiles/consts.mk
@@ -1,6 +1,6 @@
 # -*- makefile -*-
 # -----------------------------------------------------------------------
-# Copyright 2022-2023 Open Networking Foundation (ONF) and the ONF Contributors
+# Copyright 2022-2024 Open Networking Foundation Contributors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,19 +13,21 @@
 # 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.
-#
-# SPDX-FileCopyrightText: 2022-2023 Open Networking Foundation (ONF) and the ONF Contributors
+# -----------------------------------------------------------------------
+# SPDX-FileCopyrightText: 2022-2024 Open Networking Foundation Contributors
 # SPDX-License-Identifier: Apache-2.0
 # -----------------------------------------------------------------------
-# https://gerrit.opencord.org/plugins/gitiles/onf-make
-# ONF.makefile.version = 1.0
+# Intent: Defined constants for makefile use
 # -----------------------------------------------------------------------
 
 $(if $(DEBUG),$(warning ENTER))
 
-# include makefiles/constants.mk
+##-------------------##
+##---]  GLOBALS  [---##    # export(s) are visible to sub-make calls
+##-------------------##
 export dot          :=.
 export null         :=#
+export comma        := $(null),$(null)
 export space        := $(null) $(null)
 export quote-single := $(null)'$(null)#'
 export quote-double := $(null)"$(null)#"
@@ -36,7 +38,7 @@
 ##   o $(info white$(\t)space
 ##   o @echo "white$(tab)space"
 ## -----------------------------
-\t   := $(NULL)	$(NULL)
+\t   := $(null)	$(null)
 tab  := $(\t)
 
 ## -----------------------------------------------