This PR creates a support branch that only holds libmultiprocess CI scripts, documentation, and example files so these files can be removed from the master branch in #287.
This PR is a complement to #287 and the overall idea of having a support branch should be discussed there, but the CI tweaks required for this change can be reviewed here.
Note: that for testing purposes a support branch currently exists in the repo pointing at these changes. But the branch can be reset and these changes can be more properly merged in after they are reviewed.
Also note CI jobs at the bottom of this PR are expected to fail because they depend on #287. The CI jobs in #287 show the combined effects of both PRs and should succeed if they are correct.