Add mtt_check.py from Minetest Translation Tools

[Wuzzy2]

A while ago, I also wrote a .tr file checker to check for syntax errors, called mtt_check.py. You can find it here:

https://codeberg.org/Wuzzy/Minetest_Translation_Tools

Please tell me what you think about it and if it's good enough for inclusion and if not, what needs to be changed.

[appgurueu]

Looks like a sensible addition, feel free to open a PR. Though I'm not sure to which extent we want the scripts here (especially new ones) to undergo the same time consuming review process as on the minetest repo...

[SmallJoker]

Looks good. I suppose we could name it mod_translation_checker.py to be consistent with the other script.
This repository is not used/cloned as intensively, thus the review process should be relaxed. A PR would still be good to see to give potential reviewers 1 or 2 weeks of time to perform a quick sanity check before merge.