Spaces should remember window sizes

[codedread]

This will be a bit more complicated than just persisting the size to the db, since # of screens and sizes can change from when the Space was open.

[codedread]

Very similar from the original extension: deanoemcke#33

[codedread]

• When a Space is closed, remember its bounds (top, left, bottom, right) in the IndexedDB (inside SpacesService), lastBounds.
• When opening a Space, if lastBounds fully fits within the bounds of the active display, use lastBounds.
• Otherwise, use the default Space opening size.