Add local user group membership to Special:CentralAuth/Username

This information was already being queried, just adds it to the display.
The raw group names are shown, since each wiki may customize the
'group-$group' message, which we cannot access.

Bug: 18917
Change-Id: Ic0f7f1bc225b816b0b9e7ffb5407d15fb5e8f115
Merge "Add local user group membership to Special:CentralAuth/Username"