Webrtc client side (#4026)

* WebRTC Server side

* WebRTC client side

* Bug fixes and improvements

* Pushing UI improvements for webrtc (#3728)

* Pushing UI improvements for webrtc

* Updating webrtc css

* PLT-3943 WebRTC P1: bug fixes and improvements

* Video resolution set to std, reduce volume of ringtone and flip video horizontally

* Fix calling a user B while WebRTC RHS is still opened

* Leave RHS opened when call ends, Fix isBusy on popover and channel_header

* Fix pre-release feature, RHS & System Console

* PLT-3945 - Updating UI for webrtc (#3908)

* PLT-3943 Webrtc p1

* Add ongoing call indicator when RHS is opened

* UI updates to to webrtc notifcation (#3959)

webapp/sass/layout/_headers.scss

@@ -388,7 +388,8 @@
             }
         }
 
-        .channel__wrap.move--left & {
+        .channel__wrap.move--left &,
+        .channel__wrap.webrtc--show & {
             position: absolute;
             right: -400px;
             top: 14px;