Mweb 853 querystring

@nandy-andy @RafLeszczynski @rogatty I checked and all our units tests are passing, jenkins unit tests failure might be caused by sth else (?) 

BTW. Sorry for no unit tests for this, i will surely add them on Monday.
I'd change it to `$mapCityId` since `$cityId` might be confused with `$wgCityId`.