Import makefile edits from repo:voltha-docs

makefiles/include.mk
makefiles/virtualenv/include.mk
makefiles/virtualenv/patches/
makefiles/virtualenv/python_310_migration.sh
--------------------------------------------
  o Add deps and targets to create a python virtualenv
    install patched for local use of v3.10+.

Change-Id: I9a3bf8cdfc9a98f09ac84c97c0246e6194c50d01
diff --git a/makefiles/virtualenv/HOWTO b/makefiles/virtualenv/HOWTO
new file mode 100644
index 0000000..ffdc30f
--- /dev/null
+++ b/makefiles/virtualenv/HOWTO
@@ -0,0 +1,21 @@
+# Howto create a python 3.10+ patch
+
+1) Checkout voltha-docs
+2) cd voltha-docs
+3) Create a virtual environment:
+   - make venv (default python version)
+   - make venv-activate-patched (for python v3.10+)
+4) make patch-init
+5) modify the file to be patched beneath staging/${relative_path_to_patch}
+6) make patch-create PATCH_PATH=${relative_path_to_patch}
+    o This will create patches/${relative_path_to_patch}/patch
+    o make patch-create PATCH_PATH=lib/python3.10/site-packages/sphinx/util/typing.py
+      lib/python3.10/site-packages/sphinx/util/typing/patch
+7) Verify
+    o make sterile
+    o make venv
+8) Validate
+    o make lint
+    o make test
+
+# [EOF]