1268: Compile djangojs.po

Solves #1268. Does a few things, which should correlate with each individual commit:

1. Make sure we have the mo files in the language pack (#1379, commit 237208b)
2. Output djangojs.mo from kalitejs-<lc>.po we received from crowdin. (#1268).
3. In order for javascript to be able to use the translations, we shift to a dynamically generated javascript catalog file (eaea608). We used a static `en.js` before.