Add Enphase Envoy solar information

[ToddLorey]

While we're at it, here's another feature request...

Can you integrate the Envoy API into ISY Helper?

https://developer.enphase.com/docs

Having information from the solar array status and production values in ISY variables would be awesome. In particular, I might use it for a light level sensor to trigger a change in "on level" or "adjust scene" on the ISY. If it's dreary and fogging in the morning, I might want to keep the motion sense lights on later into the morning or earlier in the evening. Also might somehow use solar production information to integrate with HVAC programming.

I realize this might be hard to implement and test if you don't have a solar array with Enphase microinverters. I could give you access to my system information, if you are interested.