Init locale fallbacks
Use default locale constant rather than literal
Merge pull request #2163 from rarila/fallback-translations

Set fallback locale for translations other than the message domain
Make description field translatable
Add description to en_GB translation
Remove descriptions from contenttypes.dist.yml
Use fallback language when no entry is found in contenttypes.yml
Remove a newline in GB description
Add translated descriptions in DE
Contenttype name on overview page uses translation
Add generation of keys for groups
Add skeleton class for contenttypes translation keys
Move the generation functionality to the new class
Refactor generation from generic ct keys to its own function
Refactor generation of keys for group names to its own function
Fix groups keyprefix
Introduce a function to slugify parts of a key
Introduce a function to check if a translation for a given key is known
Introduce a function to get a fallback translation
Add en_GB translation for groups