Clubs: allow users to change privacy and more privacy option

[creativiii]

I really love clubs, however despite the several privacy settings I found that a crucial one is missing and a couple of users have asked for it:

• Everyone can see the club and its posts, but only members can participate. Users need to ask a leader to join.

This is fairly standard on Facebook Groups so I think it would be great if Clubs also supported it.

I've also noticed my users are not able to change the Club privacy settings after creating it. They have to ask me to edit it manually for them, which is fairly annoying.