Backport webrtc adapter 8.2.0 update

[tmatth]

• bower: update to webrtc-adapter 8.2.0

• package.json: update to webrtc-adapter 8.2.0

• html: update to webrtc 8.2.0

(cherry picked from commit 8032b5054eb548f269f5a895cdcbd5de0cf531ae)

[lminiero]

Merging, thx!