BHV-10787: Capture Spotlight focus in fullscreen mode.

Issue
-------
Upon initially changing to fullscreen video mode, when the pointer times out and hides, the banner and/or player controls cannot be brought back via the 5-way up/down keys.

Fix
----
We capture the `onSpotlightFocus` event via the capture API to constrain Spotlight focus to the `moon.VideoPlayer` in fullscreen mode.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>