Updating CreateRepository to interact only with stores not individual repositories

@charleso @etorreborre @raronson @markhibberd 
FWIW (and apologies for being so late) I think I'd prefer this to be `Repositories.onStore(repo) >> Repositories.onStore(repo)` (or the `for` equivalent), and the consuming code act accordingly. As mentioned elsewhere I've started to remove these when I see them, the result _feels_ cleaner. /2c