Media Controller Refactor (#517)

* Move serializeTimeRanges to utils

* Move delay() to utils

* Moved platform tests to utils file

* Moving mediaUIEventHandlers to rely on passed-in media

* Built media state def obj. No functional change yet.

* Refactored state propagation to use new MediaUISates

* Removed now unneeded Unavailable logic

* Removed use of `this` in UI event handlers

* Move UI request handlers to their own object

* Remove parens, PR request

* Remote linter item cleanup

* chore: Add newline for utils EOF.

* feat(controller-refactor). Migrate guts of controller to separate module.

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Co-authored-by: Christian Pillsbury <cpillsbury@mux.com>