Don't move windows when removing/adding monitors

[dalyIsaac]

When Windows removes a monitor, it will move windows. Based on that, Whim receives window added and window moved events.

Reproduction

Test by removing dock cable then plugging it in before Windows has a chance to reconcile.

Requirements

• Windows do not all appear on the single monitor after repro steps
• Layout is retained when restoring monitors

Proposed fix

• Ignore events until after a timer triggered by a monitor change event
• The timer will be reset by subsequent monitor change events
• After the timer completes, do a complete layout

TODOs

• Allow events for windows which aren't tracked
• Manual tests
• Tests
• TODOs
• Docs