Allow site-local configuration of available languages

added part::frontend part::i18n prio::2 type::feature workflow::blocked labels

https://github.com/EliotBerriot/django-dynamic-preferences/pull/214

No longer blocked :)!

removed workflow::blocked label

mentioned in merge request !381 (merged)

mentioned in commit d0443327

mentioned in commit 23c03b82

mentioned in commit 26a90c94

mentioned in commit bc8ecf07

mentioned in commit 2954f85a

assigned to @debdolph

closed with merge request !381 (merged)

mentioned in commit 19a4ddd5