Update release process for independent package versioning

[ni-jfitzger]

In order to support package version independence, our release process will need to change, as well as how we tag releases.

The tag naming changes will have implications for ReadTheDocs projects, as well as the LATEST_RELEASE file used by examples.rst.mako. ReadTheDocs stable version labels and maybe version labels in general expect semver tags and injecting a module name into the tag will affect its behavior (like whether it even adds the version).

See https://docs.readthedocs.io/en/stable/versions.html and https://docs.readthedocs.io/en/stable/automation-rules.html#how-automation-rules-work

[ni-jfitzger]

Possible changes: aeee08d
TODOs remaining from those changes:

• Further update build_release.py to allow specifying which packages to release.
• Update ReadTheDocs projects rules to deal with new Git tag naming scheme for releases.
• Do we need readthedocs configuration yamls?

[ni-jfitzger]

We can create a rule with a Python regex that should be able to parse the version tag and activate only if it applies to the specific product. The more challenging part is updating the "stable" version. It's automatically the latest if tag names follow semantic versions. Otherwise, we have to include "-stable" in the tag name.

For the regex that I mentioned, it may be difficult to get a "positive lookbehind" working, so we might have to use a tag format like "2.0.0-nidcpower". Inclusion of "stable" in the tag so that the stable version is updated may require experimentation and may in fact not be possible. I'm not sure if it will tolerate anything other than a semver version or a semver version followed by "-stable".

We may be forced to manage the stable version manually.