Feature: Origin-bound one-time codes delivered via SMS

* Specification: https://wicg.github.io/sms-one-time-codes/
* Implementation Status
  * Safari: [iOS 14 and macOS 11](https://developer.apple.com/documentation/safari-release-notes/safari-14-beta-release-notes)
  * Firefox: https://github.com/mozilla/standards-positions/issues/152
  * Chrome: In development as part of [Web OTP](https://github.com/WICG/web-otp)? Need clarification.