* ref(keyboard-shortcuts) refactor keyboard shortcuts to use redux

fix unsynced default value between config flag and local storage

* code review

* fix build

Create Shortcuts tab in Settings Dialog
Move keyboard shortcut option from More to this tab
Move shortcuts info from KeyboardShortcuts dialog to this tab
Remove KeyboardShortcuts dialog

Spot will need a way to submit call feedback using the iframe
api. For now expose a method on conference.js to submit that
feedback. Exposing on conference.js looks to be the existing
pattern... Also add an event to notify consumers of the iframe
api that feedback was submitted, as postMessage is async
and the notification can at least give some guarantee maybe.

I haven't updated documentation yet as I'm not confident
about this api.