Add actions on the Profile Fields admin page.

Also cleans up a bit of code formatting for the `<legend>` elemnts on this
screen.

Props slaFFik.
Fixes #5673.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9236 cdf35c40-ae34-48e0-9cc9-0c9da1808c22