Rename user admin tabs to Profile and Extended Profile

This is more consistent with WP's core nomenclature, as well as BP's other
use of the phrase 'Extended Profile'.

Fixes #5363

Props modemlooper, imath

git-svn-id: https://buddypress.svn.wordpress.org/trunk@8197 cdf35c40-ae34-48e0-9cc9-0c9da1808c22