Is there a function for issuing badges so it could be done automatically?
Topic on Extension talk:OpenBadges/Flow
There is an extension called AchievementsII which is used by the wikia farms which seems to do exactly that (I'm also for looking for an extension like this to motivate users for edits on my mediawiki). I wonder why not more people looking for an extension like this...
Unfortunately AchievementsII is not available in the MediaWiki Extension repository nor is it set up as stand alone extension (e.g. seem to be only be usable in wikia after it was activated by an admin there)
https://github.com/Wikia/app/tree/dev/extensions/wikia/AchievementsII
Maybe can create an mediawiki Badge Extension that will assign pre-set up badges after certain milestone based on the AchievmentsII one? Unfortunately I have no knowledge in creating extensions...
There is nothing built in but you could (in theory) set up a bot which uses the api in this extension to issue badges based on some trigger.