Translation of Learning Units

[stylesuxx]

As mentioned in #92:

Showing them all in one Edit Form does not really make sense in my opinion:

• The Edit form is displayed relative to the language and the learning unit
• The Form would grow substantially with each language

We can add links to every languages edit form from each edit form - I would suggest to discuss this in a new issue.

[cswertz]

Titles shouldn't be to long. Same for tags and their number. And Relations do not depend on language. So putting language (small field), title (longer field) and tags (not so long) in one line per language should be fine (even on my small screens). We can also use icons for save and delete to save space. Having a Section for "Titles" and one for "Relations" would be good.