First pass at introducing BuddyPress profile editing to `/wp-admin`:

* New `bp-members-admin.php` and accompanying assets to handle the initial admin page creation (outside of XProfile).
* New stats template functions in Blogs, Friends, and Groups components, to provide additional meta data about a members community involvement.
* Modifies some existing XProfile admin/template/filters to make it more accommodating to querying for profile data outside of BuddyPress's traditional `displayed_user` context.
* Props imath, boonebgorges, johnjamesjacoby. Fixes #5197.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7764 cdf35c40-ae34-48e0-9cc9-0c9da1808c22