Add stream selector

Initial commit - dependency on API changes
Add UX handlers for source switching
Implement API calls
Update player data and scrubber thumb rotator on switch
Merge branch '2.20-Oct-19' into streamSelector
Enable UI when source switch ended
Merge branch '2.22-Nov-30' into streamSelector
Allow updating of poster data without actually displaying it
Add enable/disable timer indicators update
Support internal changeMedia procedure

Enable performing change media with override function for
fetching/setting sources for player.
By providing checkPlayerSourcesFunction the changeMedia callout to
kalturaApi can be replaced with other logic for getting the data.
By setting the resetPlaybackValues playback values can be kept between
media changes
Update streamSelector

* Use changeMedia logic instead of switchSrc
* Enable seamless transition between streams - freeze time indicators
and display until switch is finished
Add manifest documentation
Update icon
Code cleanup
Added i18n
Use i18n service directly
Change variable name for consistency
Removed unused event binding
steamSelector fixes

1. Naming convention - use stream instead of source.
2. Add settings for key bindings.
3. Use basePlugin logger.
4. Change function name signature - avoid confusing with async API call.
Use multi request instead of two separate ones

Use one multi request instead of one with hard limit set by settings.
The hard limit is set to 4 sub streams on the main stream - and it’s
configurable via plugin settings.