metadata: add new Translation app field for URL for contributions
This is a field requested from a bunch of translators so they can easily find where to translate apps: https://forum.f-droid.org/t/translation-field-for-app-entries/1403/5
This is a field requested from a bunch of translators so they can easily find where to translate apps: https://forum.f-droid.org/t/translation-field-for-app-entries/1403/5