Add 921600 cpc baudrate.

[BrianPugh]

Adds an option to set CPC baudrate to 921600. I haven't had an opportunity to test this on hardware (I don't want to develop on the zigbee stick that's running my house), but no reason it shouldn't work.

Follow up on Nerivec/ember-zli#12 .

[puddly]

You can specify the CPC baudrate over CLI via --cpc-baudrate 921600 if your firmware uses a different baudrate.

The default baudrates are iterated over, one at a time, every time an adapter is probed. Each new option unfortunately slows down probing so I don't think this will be a good change to have globally.

[Nerivec]

A better option might be to make the params available through the web flasher (advanced section or something)?

[puddly]

The baudrate config is exposed in the manifest.json so any deployment can add it to the list: https://connectzbt1.home-assistant.io/firmwares/manifest.json

[Nerivec]

I was thinking more in a way that allows to set the baudrate directly to avoid the probing entirely (same for type), from within the web flasher. But since the config allows probing customization (partly solving the original issue), that'd be more of a new "feature" to have.