Added support for opensearch

When ExtendedSearch is enabled, the default opensearch urls are overwriten
that the request triggers ExtendedSearch and not MediaWiki standard
search.

 * Fixed typo

Change-Id: I3274d894f1bd5f37a2e08a012b12fccb6408b857
Renamed autocomplete file

Autocomplete is not a widget so remove this part from the filename. Also removed
unnecessary closure because in mw.loader it is already in a closure.

Change-Id: Id7711d6ec24d677201356cffbfb1563c93a239b3
Merge "Added support for opensearch"
Merge "Renamed autocomplete file"