Is your feature request related to a problem? Please describe.
After #216 it would be nice to export song translation, if they exists for a song.

Describe the solution you'd like

• Extend SongDrive preferences with options, that define the languages that should be translatable. For now it should be sufficient to just use the users preferred language as "origin" and only translate all songs in other languages into this one.
• Extend OpenLyrics XML with formatted translated lines
• Translations should be appended block-wise for each slide

Additional context
Follow up to #216