Rewrite of NamespaceNuker

All options of NamespaceNuker did not work or not correctly. I rewrote the
code of it because it is much easier to use MediaWiki. The benefit is that
many steps are done by MediaWiki and there is no need that we do them.

 * Fixed bug with not correctly shown message in remove dialog
 * Corrected names of alert windowalert windows

Change-Id: I65c5a3ec7440563a3373fa1f572b33f312befa50
Merge "Rewrite of NamespaceNuker"