Plan for supporting Nest

[haxorcize]

First off -- this is such an incredible project! I also like your code, it's clean and seems to be easily extensible.

Wondering if you know of anyone adding Nest cameras?

The https://github.com/Brandawg93/homebridge-nest-cam project seems to have reverse engineered the nest app protocol, but seems like Google finally released proper APIs for device access on these nest devices, and you can generate a (seems to be) private RTSP stream. If that's really the case, it would seem simple enough to extend as a new camera type. Wondering if someone did it already though? :)

https://developers.google.com/nest/device-access/api/camera