Extract translations for the Add Extension modal
Extract translations for the Add Extension modal

- Extracts three translations for this placeholder dialog.
- Adds a forum link to one of the translations.

malayladu/core,renyuneyun/core,malayladu/core,Luceos/core,malayladu/core,flarum/core,datitisev/core,Luceos/core,flarum/core,flarum/core,Luceos/core,datitisev/core,datitisev/core,datitisev/core,Luceos/core,renyuneyun/core,renyuneyun/core,malayladu/core,renyuneyun/core