Import translations from Transifex for Icehouse

* Import ~100% completed translations
  We have three languages: German, Serbian and Hindi in Icehouse :-)
* Update language list in openstack_dashboard settings.py
* Update English POT files

This commit also updates compiled PO files (.mo). There is
a discussion compiled PO files should be included in the repo
or not, but it is better to be unchanged in this release.

Update Transifex resource name in .tx/config for Icehouse.

Closes-Bug: #1300290
Change-Id: I0c378e885efc4ecdafdd5d6b027a514a5af5bb2f