Install venv patched for target use.

This patch is intended for local development use.
It will allow more makefile targets to use an upgraded python interpreter (3.10+)

Makefile
--------
  o Change venv activate script dependency for three lingering targets
    from $(venv-activate-script) to $(venv-activate-patched).
  o venv-activate-patched supports local python v3.10+ use.
  o Added target voltha-docs-catchall to support testing.

[HOWTO: Test]
  % make sterile help
  % make sterile multiversion
  % make sterile voltha-docs-catchall

Change-Id: Id5f6c29c73bc11cc511fe83838fc234133d38ebf
diff --git a/Makefile b/Makefile
index f99c809..4b22336 100644
--- a/Makefile
+++ b/Makefile
@@ -167,7 +167,7 @@
 ## -----------------------------------------------------------------------
 ## Intent: build multiple versions
 ## -----------------------------------------------------------------------
-multiversion: $(venv-activate-script) Makefile | prep $(OTHER_REPO_DOCS)
+multiversion: $(venv-activate-patched) Makefile | prep $(OTHER_REPO_DOCS)
 	$(activate)\
  && sphinx-multiversion "$(SOURCEDIR)" "$(BUILDDIR)/multiversion" $(SPHINXOPTS)
 	cp "$(SOURCEDIR)/_templates/meta_refresh.html" "$(BUILDDIR)/multiversion/index.html"
@@ -183,7 +183,8 @@
 ##         library makefiles do more so transfer control only when needed.
 ## -----------------------------------------------------------------------
 include $(ONF_MAKEDIR)/voltha/docs-catchall-targets.mk
-$(voltha-docs-catchall): $(venv-activate-script) Makefile | $(OTHER_REPO_DOCS) $(STATIC_DOCS)
+voltha-docs-catchall : $(voltha-docs-catchall)
+$(voltha-docs-catchall): $(venv-activate-patched) Makefile | $(OTHER_REPO_DOCS) $(STATIC_DOCS)
 	@echo " ** CATCHALL: $@"
 	$(activate)\
  && $(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
@@ -191,7 +192,7 @@
 ## -----------------------------------------------------------------------
 ## Intent: Display makefile target help
 ## -----------------------------------------------------------------------
-help :: $(venv-activate-script)
+help :: $(venv-activate-patched)
 	@ echo
 	$(HIDE)$(activate) \
  && $(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)