New Catalan translation

The current Catalan translation is quite bad. Bad enough to be unusable, because the "human translation" don't follow the standards for Catalan software translations, and worse, much of the file was autogenerated by Google Translator, and in a large part the result was really bad.

I have done a new translation from scratch, basing on the Catalan file from the addons/nuxeo-platform-lang-ext repository in hg. After finishing the work, I've noticed many strings are still missing, apparently because the Catalan file in HG wasn't up to date/synced with the English and French files.

While I get help to fix this, applying this would be a HUGE step forward in order to get a working Catalan translation.