Enable RCFilters app on Watchlist
* Add classes prefixed with cl (for ChangesList)
to both RC and WL so that the JS app can locate
similar elements using the same selectors
* Make saved queries preference name configurable
so that RC and WL use different preferences
* Move some code from SpecialRecentchanges.php to
its base class so it's accessible to SpecialWatchlist.php
To use the RCFilters app on WL, append ?rcfilters=1 to the URL
Bug: T171132
Bug: T171218
Change-Id: If7c63284224df24fa02022b4ea74bef116f28ca6
12 files changed: