Prepare stable release

[indigoxela]

It's been a while, the module is in use, so maybe it's time for a stable release.

TODO:

• Cleanup the issue queue (most issues seem outdated)
• Cleanup code where appropriate, at least do a final review
• Revisit GHA workflow

[laryn]

I suggest bumping your version number when you do to match the D7 version. e.g. here's how the Backdrop Upgrade Status module compares the two right now (it looks like the Backdrop version is outdated at 1.0.0 vs. the D7 version at 1.31):

[indigoxela]

From that perspective (1.31 vs. 1.0.0-betaX) displayed, it seems like we should bump.

On the other hand the B version required a lot of rewrites (modules gone, functionality went to core...) and the module just isn't in a "stable" state yet (feature-wise).

Two big blockers:

• Translation groups, see #87
• Still overlapping functionality (node/terms...), possibly it will even get worse #38

If we followed the Drupal versions, we'd have to do stable releases - but I hesitate, because of the blockers.