User roles control

Folks with 'owner' role should be able to set/remove 'moderator' or 'administrator' bits on other users.

Frontend

Simplest thing for now is to have a user-role control button on the profile page, alongside the block/moderate/etc controls.

Need to be able to:

• set/unset moderator
• set/unset administrator

Perhaps show as a popup menu like the moderator controls, with state buttons for each inside?

For now we don't need a big user list or anything.

Mockup

Maybe something along these lines?

Backend

This part's easy!

       $user->grantRole($role);
       $user->revokeRole($role);