Notifications centralization

Per a comment on #4928 - we need notifications to be more coherent.

On the implementation side the receivers and services can be streamlined, and the UI in particular needs to be implemented in a single place.

First job is to define what that means:

I had some visions on "what should notifications look like" - similar to your thinking on a unified control panel for auto-syncing, I think notifications should be in a single spot (though I'm not 100% against an entry in Deck Options, I'd have it connect to a main notifications control panel)

On that sub-preference, I'd see a top section that indicates can configure global vibration and LED setting, that you can turn on or off a global notification for total work due, and you can set a threshold for that work. While the current global notification is slaved to "start of day" time right now I think it would be nice to set the time.

Then under a divider, I could see a recycler view of decks, with checkboxes of reminders per deck, then the deck name, then the notification time. If that's two cramped, I'd show checkboxes and deck name and pop up the time dialog for edit. Bonus points for making the checkboxes and deck title sortable.

I want the deck notifications to actually be per-deck, not per-deck-options (as they are now) but I'm not sure if that's possible. If it is not possible then I'd have the scroll be for deck options and when you click in to it, you see which decks are using it. I really don't like that but it's only if I can't do per-deck at all - I'm simply unsure on that point.