Add user rights 'viewmywatchlist', 'editmywatchlist'

These are needed for OAuth grants.

Note that, even if 'editmywatchlist' is not granted, various actions
will still allow for adding but not removing of pages.

Change-Id: Ie33446a228dd6ed0114730935c1bf65667f5ce01
Merge "Add user rights 'viewmywatchlist', 'editmywatchlist'"