[VOL-5297] - (dep for) Install pre-commit linting tool

.gitmodules
lf/onf-make
-----------
  o Add repo:onf-make (library makefiles) as a git submodule of the repo.
  o Submodule onf-make replaces legacy makefiles/ copy & paste logic
    with a common set of makefiles used across all voltha repositories.

lf/README.md
lf/include.mk
lf/local/include.mk
-------------------
  o Early config: install makefile loader(s) include.mk.

Change-Id: I4a8a94fc0fba64a7ab2a7192e935ba143e199cef
Signed-off-by: Joey Armstrong <jarmstrong@linuxfoundation.org>
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..0b23d6f
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "lf/onf-make"]
+	path = lf/onf-make
+	url = https://gerrit.opencord.org/onf-make
diff --git a/lf/README.md b/lf/README.md
new file mode 100644
index 0000000..6ecec93
--- /dev/null
+++ b/lf/README.md
@@ -0,0 +1,14 @@
+Library makefiles
+=================
+
+$(sandbox-root)/include.mk
+    Source this makefile to import all makefile logic.
+
+$(sandbox-root)/lf/onf-make/
+$(sandbox-root)/lf/onf-make/include.mk
+    repo:onf-make contains common library makefile logic.
+    tag based checkout (frozen) as a git submodule.
+
+$(sandbox-root)/lf/local/
+$(sandbox-root)/lf/local/include.mk
+    per-repository targets and logic to customize makefile behavior.
diff --git a/lf/include.mk b/lf/include.mk
new file mode 100644
index 0000000..5d52907
--- /dev/null
+++ b/lf/include.mk
@@ -0,0 +1,109 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2023-2024 Open Networking Foundation Contributors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# -----------------------------------------------------------------------
+# SPDX-FileCopyrightText: 2023-2024 Open Networking Foundation Contributors
+# SPDX-License-Identifier: Apache-2.0
+# -----------------------------------------------------------------------
+
+$(if $(DEBUG),$(warning ENTER))
+
+## -----------------------------------------------------------------------
+## Infer path to cloned sandbox root
+## [TODO] Deprecate TOP=
+## -----------------------------------------------------------------------
+lf-sbx-root   := $(abspath $(lastword $(MAKEFILE_LIST)))
+lf-sbx-root   := $(subst /lf/include.mk,$(null),$(lf-sbx-root))
+
+## -----------------------------------------------------------------------
+## Define vars based on relative import (normalize symlinks)
+## Usage: include makefiles/onf/include.mk
+## -----------------------------------------------------------------------
+onf-mk-abs    := $(abspath $(lastword $(MAKEFILE_LIST)))
+onf-mk-top    := $(subst /include.mk,$(null),$(onf-mk-abs))
+onf-mk-lib    := $(onf-mk-top)/onf-make/makefiles
+onf-mk-loc    := $(onf-mk-top)/local
+
+TOP           ?= $(patsubst %/makefiles/include.mk,%,$(onf-mk-abs))
+
+## -----------------------------------------------------------------------
+## This variable is a bridge to help transition away from legacy makefiles.
+## -----------------------------------------------------------------------
+legacy-mk     := $(lf-sbx-root)/makefiles
+
+## ------------------------------------------------------
+## Two distinct vars needed to access library or project
+## ------------------------------------------------------
+ONF_MAKEDIR ?= $(onf-mk-lib)
+MAKEDIR     ?= $(onf-mk-loc)
+
+# -----------------------------------------------------------------------
+# Load per-repository conditionals
+# Load late else alter MAKEFILE_LIST
+# NOTE: config.mk can be removed if dynamic feature detection by
+#       file extension is added.
+# -----------------------------------------------------------------------
+include $(wildcard $(lf-sbx-root)/config.mk $(lf-sbx-root)/lf/config.mk)
+
+## -----------------------------------------------------------------------
+## Load makefiles in order:
+##   1) Library constants and logic loaded first
+##   2) Parameterize and augment targets from local (repo specific)
+## -----------------------------------------------------------------------
+include $(onf-mk-lib)/include.mk
+include $(onf-mk-loc)/include.mk
+
+## Define late so caller (?- env --ignore-environment -?)
+GIT ?= /usr/bin/env git
+
+## -----------------------------------------------------------------------
+## Intent: This target will update dependent git-submodule to the latest
+##         version available from the remote repository.  Subsequently
+##         a checkin will be needed to make the submodule update permanent.
+## -----------------------------------------------------------------------
+.PHONY: update-git-submodules
+update-git-submodules:
+	$(GIT) submodule foreach git pull
+
+## -----------------------------------------------------------------------
+## Intent: On-demand cloning of git submodule(s).
+## -----------------------------------------------------------------------
+## Trigger: include $(onf-mk-lib)/include.mk
+##   - When the make command attempts to include a makefile from the
+##     repo:onf-make submodule, this target/dependency will initialize
+##     and checkout all submodules the current repository depends on.
+## -----------------------------------------------------------------------
+.PHONY: git-submodules
+git-submodules : $(onf-mk-lib)/include.mk
+
+$(onf-mk-lib)/include.mk:
+
+	$(call banner-enter,(Checkout git submodules))
+
+	$(GIT) submodule update --init --recursive
+
+	$(call banner-leave,(Checkout git submodules))
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+help-git :
+	@printf '  %-33.33s %s\n' 'git-submodules' \
+	  'Init and recursive checkout of git submodule(s)'
+	@printf '  %-33.33s %s\n' 'update-git-submodules' \
+	  'Update git submodule(s) to the latest version'
+
+$(if $(DEBUG),$(warning LEAVE))
+
+# [EOF]
diff --git a/lf/local/include.mk b/lf/local/include.mk
new file mode 100644
index 0000000..a0dedcc
--- /dev/null
+++ b/lf/local/include.mk
@@ -0,0 +1,26 @@
+# -*- makefile -*
+# -----------------------------------------------------------------------
+# Copyright 2017-2024 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.
+# You may obtain a copy of the License at
+#
+# http:#www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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: 2017-2024 Open Networking Foundation Contributors
+# SPDX-License-Identifier: Apache-2.0
+# -----------------------------------------------------------------------
+# Intent: This makefile is the top level source for including
+#         per-repository makefile logic and configs.
+# Import hierarchy:
+#   Makefile      -> lf/include.mk
+#   lf/include.mk -> lf/onf-make/include.mk    # library makefiles
+#   lf/include.mk -> lf/local/include.mk       # per-repo makefiles
+# -----------------------------------------------------------------------
diff --git a/lf/onf-make b/lf/onf-make
new file mode 160000
index 0000000..ccab2cf
--- /dev/null
+++ b/lf/onf-make
@@ -0,0 +1 @@
+Subproject commit ccab2cf3fae8eba44577287c1b396ccb4861ecc9