Translations, Twitch and little things

• Translation workflow has been completely changed to use crowdin.
• Half-broken twitch URL import has been removed - download the zip files and import them manually instead.
• Also, bugfixes, and a pile of small changes!

See full changelog:
https://github.com/MultiMC/MultiMC5/blob/d58481e0de15ec4f1eb60de9a42c6cc9ec330d86/changelog.md