Create new group privileges

-if user creates group and does not have privileges for its management, he automatically becomes group manager of the newly created group.
I didn't use the AuthzResolver from blimpl package, because I couldn't get to it. Interface for AuthzResolverBlImpl is non-existent, I cannot get to any methods. Should I do another commit (in other words, another pull request) where I add the methods to the interface so that I can fix this commit?