New Watch button state

The behaviour of watch buttons have changed to be more accurate regarding users' custom notification filters: if users have filters concerning some specific events only (e.g. a filter to watch mention on the whole wiki) the watch buttons will be displayed as "undecided". The idea is to expose to the users that "some events" are actually watched for that page, space or wiki.

Also using the watch buttons might disable some already existing custom filters, if those are concerning the exact same location and are contradictory. So for example, if a filter has been created to ignore mentions on a specific space, and the user decides to watch this space, then automatically the filter to ignore mention will be disabled. It can be enabled back manually by the user through the notification settings.