[nest] Add support for WebRTC streaming

[jannegpriv]

Add support for WebRTC streaming, that is used for newer Google Nest cameras/doorbells, e.g.

• Nest Cam (outdoor, battery)
• Nest Cam with floodlight
• Nest Doorbell (battery)
• Nest Doorbell (wired, 2nd gen)

The documentation for google API contains information about how to implement WebRTC live streaming.

[osteves071]

I like this idea to upgrade the Binding as I do own a Nest Doorbell Gen 2 (wired), I do have two questions: 1) Does Openhab support webRTC? 2) I heared, that Google is planning to decommission the SDM platform and move on to Matter?

Depending on the answer to question 1, I already pulled the sources for the Binding and added the code that from my point of view would be required to make it work, unfortunately this Pull was based on the current development and I do not have a test instance running with 4.2 Milestones only a productive 4.1 version.

Said that, if openhab handles webRTC properly, I can give my code a try and provide it for the community.