Update po4a scripts for better markdown support

[ignotus666]

Short description of changes Update po4a and workflow scripts to better support markdown, and display errors (but not fail) when there are tag inconsistencies in html files. The po4a cache has been renamed to force the creation of a new one with the updated version of po4a in the assets repo. The updated po4a scripts will not work with the old version as new options have been introduced, so this PR and this one should be merged at the same time. In any event, I think #870 should be merged before this PR to avoid possible conflicts (e.g. it would happen if this PR gets merged and afterwards the EN files get updated).

The stats script has been removed as with Weblate it's become redundant.

The next time the .po files are updated, a number of strings in each language will become fuzzies - it will mostly just be a matter of removing characters (`#, ```` and maybe others) in the fuzzy strings.

Context: Fixes an issue? Related issues Fixes #817

Status of this Pull Request Should be ready.

What is missing until this pull request can be merged?

Does this need translation?

No.

Checklist

• [x] I've verified that this Pull Request follows the general code principles
• [ ] I waited some time after this Pull Request was opened and all GitHub checks completed without errors.
• [x] I'm sure that this Pull Request goes to the correct branch

[ignotus666]

Note: the check fails because it looks for po4a version 0.68, which isn't yet in the assets repo.

[ann0see]

Could you please check the validity of this again? Locally I don't see a translation for any language.

[ann0see]

Ok. Got it. Maybe the threshold is too high?

[ignotus666]

The new markdown processing in this PR causes a lot of strings to become fuzzies, which is why the threshold isn't reached for so many files. They're easy to update, as it's just a matter of removing a few characters, so I'd leave the threshold as it is. It will take some effort to do though, as there are quite a few languages now. But in the long run we'll have "cleaner" strings for translators.

[ignotus666]

Also, I think it would be better to get this in before all the changes to the EN files that are happening, so they get processed in the "new" way.

[ann0see]

Yes, but this will make the production site largely untranslated

[ignotus666]

Ahh, true... So maybe we can make this PR against next-release then?

[ann0see]

We could. It's not perfect. Especially since this will make the build fail on release – unless we re-upload the old po4a deb and use different links.

[ann0see]

Let’s merge this to next release.