Merge changes from forks

### Describe the problem

Believe it or not, I looked through all the forks and collected some with considerable changes that have not been merged in this repo (update: should have tried something like this https://github.com/mvoggu/forksAhead). I, however, have not thoroughly inspected each one on what can be merged.
I only looked at those whose default branch has diverged from this repo's, so some I might have overlooked.

Here's the list:

* https://github.com/vendasta/weblate - added a lot of deployment files, but there are also source-code changes, like the addition of namespace languages (?). Not sure how much of it can be merged.
* https://github.com/WeblateOrg/weblate/compare/main...dmitmel:stable-crosscode - autocompletion, API endpoints, some fixes, settings changes
* https://github.com/qinthq/weblate - added UWAI (?) addon.
* https://github.com/WeblateOrg/weblate/compare/main...chervol:master - some minor changes, idk
* https://github.com/WeblateOrg/weblate/compare/main...alvinchen977:main - fuzzy date parsing for `search.py`.
* https://github.com/CivicDataLab/Anuvad - heavy customization, but no valuable source code changes.
* https://github.com/ValdasRK/weblate - one commit https://github.com/ValdasRK/weblate/commit/b543d88bd1dba626d34bc619247fe6ce3246b533

### Describe the solution you'd like

Check out the repos and merge what's useful.

### Describe alternatives you've considered

_No response_

### Screenshots

_No response_

### Additional context

Inspired by [this discussion](https://github.com/WeblateOrg/weblate/issues/1548#issuecomment-313933747). I've also made a copy of some of these in my fork, just in case.