feat: add Danish translations

[birjj]

Adds a translation for Danish.
I've used the translation of "Search" for the cmfcmf/d-s-l.searchBar.submitButtonTitle (instead of the translation of "Submit", as used in en.json). I've chosen to do this because the translation of "Submit" ("Indsend"/"Send") is rarely used in the given context in Danish. This is similar to de.json.