Fix multiversion builds

This includes:
* Revert switch to onf-make: onf-make was never compatible with
  this repo. For now, we want to revert these changes so that the
  build can work properly again.
* Re-enable static builds: the latest updates don't require removing
  patching from voltha-system-tests or cord-tester to work. The build
  also succeeds if patching is removed, so that is a likely future
  change to those repos.
* Switch to an updated custom version of sphinx-multiversion: though
  originally forked from zdw for the purpose of making changes to the
  prep step or other functionality, none was necessary. However, the
  latest changes to the mainline sphinx-multiversion have now been
  brought into the fork, with zdw's prep additions included.

Signed-off-by: Eric Ball <eball@linuxfoundation.org>
Change-Id: I0afb08030edcae4d2e968c63ef5eb11e17085d8a
diff --git a/requirements.txt b/requirements.txt
index 5838cbc..83356ed 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -23,7 +23,7 @@
 recommonmark~=0.7.1
 doc8~=1.1.2
 docutils~=0.21.2
-sphinx-multiversion~=0.2.4
+git+https://github.com/eb-oss/sphinx-multiversion@main
 sphinx-reload~=0.2.0
 sphinx-rtd-theme~=3.0.2
 sphinxcontrib-openapi~=0.8.4