Downgrade video codec when encoding CPU usage is high or hardware encoder fail

[shi-su]

Issue #:

Description of changes: Downgrade video codec when encoding CPU usage is high or hardware encoder fail

Testing: Tested codec degradation from software encoder CPU usage with a lowered threshold.

Can these tested using a demo application? Please provide reproducible step-by-step instructions. No

Checklist:

1. Have you successfully run npm run build:release locally? y

2. Do you add, modify, or delete public API definitions? If yes, has that been reviewed and approved? n

3. Do you change the wire protocol, e.g. the request method? If yes, has that been reviewed and approved? n

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.