PLA-1857 Wiki Syndication Blacklist support

My thinking was: I wanted to show in every child classes that I'm applying the filter (as it is one-liner), but not necessarily redefine filterQuery in every class - as the filter query is the same. That would provide to the conclusion of moving execution of this function to getSelect as you suggested before, but I  don't like this idea because of  not being explicit. Basically, for new user  of the class it would be harder to debug why some wikis are excluded.