Make admin menu smaller

There are lots of admin options when you're super admin. It makes the
menu too long if your screen isn't as big as Robin's.
More meaningful name for bag_labels pdf
Beginning of Club Admin Functionality
Attempt at making admin/registrants/club actually list club members

Note, there is no path to admin/registrants/club yet
Added text string in DB for User.club, migrate.
Small club admin update
Attempt at fixing club bug

If club field in admin/users is blank, it should set club_admin to
false. It doesn't right now.
Merge scott's club_admin work, fix the update-club-name-on-user-model. Set up the admin/registrants/club route.