Grant service access by permissions

Implements #663 (closed)

Not a whole lot to say about this really. Give a User or Group the required permission and they'll be able to access the service. This allows more granular access to certain services (SeAT was the progenitor for this change).

All of the old ENABLE_AUTH/BLUE_<servicename> settings are gone. You enable services now by having them active in INSTALLED_APPS. You give users access by giving the permission to access that service. Theoretically speaking, provided the user has an API entered and a main character selected, you could quite happily manually grant access to services for non-member and non-blue users if you so desired. Though I have not explicitly tested this. Some of the services still rely on user states for name formatting and may fail, though a name formatting update is on the road map.

The migration will attempt to detect the old service enabled settings and add permissions to their respective groups (Member or Blue or whatever you've changed the defaults to) automatically.