[VOL-5010] - Clone unit tests to run on a v2.12 branch

docs/release/README.md
makefiles/release/help.mk
-------------------------
  o Temp release documentation until text can be o-fficially
    added in the howto:release section of docs.voltha.org.

Makefile
makefiles/include.mk
makefiles/release/include.mk
makefiles/release/required.mk
makefiles/release/targets.mk
-----------------------------
  o Add makefile infra used to create and clone master tests for release.
  o Logic is conditional, makefile library will only load when named
    targets are requested.
  o make help and make help-voltha-release document new targets.
  o create-jobs-release-nightly is simply a placeholder for now.
    - Nightly unit tests are still bundled in the mega voltha job config.
    - Still need to isolate and separate these out so tests can be
      anchored for branch driven release testing.

Change-Id: I692166e17c5e04d87d112f317b9fead1d5c4090d
diff --git a/makefiles/release/help.mk b/makefiles/release/help.mk
new file mode 100644
index 0000000..fde2d0e
--- /dev/null
+++ b/makefiles/release/help.mk
@@ -0,0 +1,33 @@
+# -*- 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.
+# -----------------------------------------------------------------------
+# Intent: Helper makefile target used to setup for a release
+# -----------------------------------------------------------------------
+
+## ---------------------------------------------------------------------------
+## Intent: Display supported targets
+## ---------------------------------------------------------------------------
+help-voltha-release :
+	@echo
+	@echo '[RELEASE] - Create branch driven testing pipelines'
+	@echo '  create-jobs-release'
+	@echo '  create-jobs-release-nightly Nightly testing'
+	@echo '  create-jobs-release-units   Unit testing'
+
+help ::
+	@echo '  help-voltha-release Display voltha release targets'
+
+# [EOF]