Send an email to moderator of a group when it is created through the API?

[tibetsprague]

• [x] different email if the user already exists or not? If doesn't exist and we create the user first then how could we avoid sending two emails, one to finish registering and one about the group? Maybe we don't send the group email if the user is inactive, that would work. - ok to send two emails for now if we have to
• [x] Also should the group be inactive until they register (or log in?) and then we activate it? For now we decided that group can be active.