[VOL-5009] - Update release notes

config.mk
makefiles/*
-----------
  o Refresh library makefiles from https://github.com/opencord/onf-make.
  o More lint targets added with exclusions in config.mk

makefiles/virtualenv.mk
patches/lib/python3.10/site-packages/robot/utils/normalizing.py/patch
patches/lib/python3.10/site-packages/robot/utils/robottypes3.py/patch
patches/python_310_migration.sh
---------------------------------------------------------------------
  o Continue normalizing virtualenv install directory.
  o Update patches to modify .venv VS vst_venv [, vdoc_venv, vfoo_venv, vbar_venv, ...)
  o virtualenv.mk now defines named targets for patching-up-to 3.10 installs.

release_notes/voltha_2.12.rst
-----------------------------
  o Update version string info.
  o Onos component table condensed and populated with versioned urls.
  o voltha components table is a WIP.

howto/release/repositories/
---------------------------
  o Begin capturing repo-specific activities for release.
  o Silly having to figure this out each release cycle.
  o Automation and release helper scripts can be found here:
    - https://github.com/joey-onf/voltha-release

sphinx_conf/exclude_patterns.py
-------------------------------
  o Roach squashing exercise, external repos pulled in as git-submodules.
  o New repository files appear as problems when running 'make reload'
  o Exclude files to squelch messages.

Change-Id: I7adf7b84498511f5cde1e43ad304f9e33283241e
diff --git a/makefiles/targets/sterile.mk b/makefiles/targets/sterile.mk
new file mode 100644
index 0000000..c661f53
--- /dev/null
+++ b/makefiles/targets/sterile.mk
@@ -0,0 +1,45 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2022-2023 Open Networking Foundation (ONF) and the ONF 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: 2022-2023 Open Networking Foundation (ONF) and the ONF Contributors
+# SPDX-License-Identifier: Apache-2.0
+# -----------------------------------------------------------------------
+
+$(if $(DEBUG),$(warning ENTER))
+
+## -----------------------------------------------------------------------
+## Intent: Revert sandbox into a pristine checkout stage
+## -----------------------------------------------------------------------
+##   Note: Sterile target behavior differs from clean around handling of
+##         persistent content.  For ex removal of a python virtualenv adds
+##         extra overhead to development iteration:
+##           make clean   - preserve a virtual env
+##           make sterile - force reinstallation
+## -----------------------------------------------------------------------
+.PHONY: sterile
+sterile :: clean
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+help-verbose += help-sterile
+help-sterile ::
+	@echo
+	@echo '[MAKE: sterile]'
+	@echo '  sterile             make clean, also remove persistent content (~venv)'
+
+$(if $(DEBUG),$(warning LEAVE))
+
+# [EOF]