Add adaptive simulcast

[timmydoza]

Contributing to Twilio

All third party contributors acknowledge that any contributions they provide will be made under the same open source license that the open source project is provided under.

• I acknowledge that all my contributions will be made under the project's license.

Pull Request Details

JIRA link(s):

• AHOYAPPS-0000

Description

A description of what this PR does.

Burndown

Before review

• Updated CHANGELOG.md if necessary
• Added unit tests if necessary
• Updated affected documentation
• Verified locally with npm test
• Manually sanity tested running locally
• Included screenshot as PR comment (if needed)
• Ready for review

Before merge

• Got one or more +1s
• Re-tested if necessary