Debug-level logs, multi-viewer interface, and more tooltips

[sirknightj]

Issue #, if available:

Description of changes:

• Master now can show multiple viewers

(pictured above: master and two viewers, with the mock video source: open -a "Google Chrome" --args --use-fake-device-for-media-stream. Make sure chrome is not running before launching otherwise the webcam might still show.)

• High-level overview

  • When a new viewer connects, a new video element is added to the page, below the previous one.
  • When the peer connection moves to the FAILED state, the video element is removed from the page.
  • The viewer's ClientId is added below each video's media tracks.
  • When the master has no viewers connected, an empty video player will be shown.

• Add DEBUG log level

  

• log SDP offer and answer in DEBUG

• log generated ICE candidates in DEBUG

• log selected ice candidate in DEBUG

• log when the peer connection is successful or unsuccessful in DEBUG

• Add tooltip for ICE Candidate generation

  

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Fixed an issue with "Enable KVS WebRTC DQP Test and Metrics (Viewer only)" if the ClientId is empty, the display would generate a new one with each update.

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[sirknightj]

See #234 for original conversation