Add flags to groups so staff approval for channel takeovers and cloaks can be skipped

[errietta]

@tomaw does it also skip cloak approval by the user ?

[JRHaigh]

It would probably also be worth the flags having an intermediate option to only notify network staff of changes. I.e., to have these 3 options:

• require staff approval;
• only notify staff;
• no staff involvement.