SUP-2939 #comment Support CORS headers for AJAX requests #time 1d

Enable passing ajax options object to query implementation of ajax in
the mediaWiki library.
Currently added support for xhrFields “withCredentials” which is set by
default to true.
In case VAST server is returning “Access-Control-Allow-Origin” header
set to “*” then request will fail due to security error of CORS so in
this case VAST needs to be configured with enablers flag set to false.