Adding mongolian language configs and various translation improvements

[spacekookie]

This addresses issue #669.

@Svenyo Please upload these files to transifex so that they can get started on the translation process

[spacekookie]

Okay, after checking the issue again I saw that the files were already translated into mongolian. Sorry about that!

I pulled the translations and generated the assets. Will test this and can then deploy it to staging.

Note This doesn't include any of the translations for the recent GDPR update yet, I guess we will have to update the translations again once they become available from transifex?

[1000miles]

@spacekookie Thanks for the PR. Can you please remove the 3 resource files that are not needed/used for translations? You can compare the list via the list in the wiki here: https://github.com/sozialhelden/wheelmap/wiki/Translation-Guide.

Yes, usually when we already have the translations via tx pull this means someone already uploaded the resource files to transifex. :)