add an alternate video recording widget for testing

We fixed some problems in the video recording widget that
we want to test in a real production environment. So the
updated widget is behind a flag in the plugin settings

Test Plan:
 * Enable the "Use alternative flash recording widget"
   checkbox under kaltura plugin settings
 * You can tell it's the new widget if when it loads, and
   you have 2 cameras, it'll present with an option to choose

closes CNVS-12037

Change-Id: Iaf360874c5c3078ae421dfce1977579fedf1f19c
Reviewed-on: https://gerrit.instructure.com/32417
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Nathan Rogowski <nathan@instructure.com>
Product-Review: Bracken Mosbacker <bracken@instructure.com>