Localize collaboration settings. (#3100)

Closes #2764

conf/locale/locale_en-US.ini

@@ -561,6 +561,10 @@ wiki.last_updated = Last updated %s
 settings = Settings
 settings.options = Options
 settings.collaboration = Collaboration
+settings.collaboration.admin = Admin
+settings.collaboration.write = Write
+settings.collaboration.read = Read
+settings.collaboration.undefined = Undefined
 settings.hooks = Webhooks
 settings.githooks = Git Hooks
 settings.basic_settings = Basic Settings