Move save, close and later button into menu

This change moves *Save*, *Close* and *Later* buttons into the action bar or menu so that changes can be made without closing the keyboard or scrolling first. I wanted to implement a custom action bar first, but I ended up preferring a simpler solution: *Save* is always going to be at the very right side of the action bar, *Close* the first item of the menu, and *Later* (still no clue what people use this for) the second entry when adding cards.

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