This PR adds a new "Pause notifications" checkbox to the user status modal. This checkbox allows enabling the Do-Not-Disturb mode together with user status. Note that we don't remove and don't rename the existing DnD menu item in this PR, so the old way of entering the DnD mode is still available.
Also, we're not making DnD mode a part of user status on backend and in database. The reason is that the DnD mode should still be available on sites with disabled user status, having them separated helps keep the implementation simple.
Andrei Prigorshnev