feat(e2ee) add support for WebRTC Encoded Transform

An alternative to Insertable Streams, currently implemented in Safarii / WebKit.

https://w3c.github.io/webrtc-encoded-transform/

It's currently behind a config flag, both in Safari and here.

Fixes: https://github.com/jitsi/jitsi-meet/issues/9585

config.js

     // bridge itself is reachable via UDP)
     // useTurnUdp: false
 
+    // Enable support for encoded transform in supported browsers. This allows
+    // E2EE to work in Safari if the corresponding flag is enabled in the browser.
+    // Experimental.
+    // enableEncodedTransformSupport: false,
+
     // UI
     //
 

react/features/base/config/configWhitelist.js

     'e2eping',
     'enableDisplayNameInStats',
     'enableEmailInStats',
+    'enableEncodedTransformSupport',
     'enableIceRestart',
     'enableInsecureRoomNameWarning',
     'enableLayerSuspension',