Adds method to hit the solar 'history' API endpoint.

[ArthurD]

Very basic PR that is largely a copy/paste from the existing solar method/API call directly above it. This allows you to pull the 'solar history' for a given energy site (energy_site_id).

I used args instead of adding to the existing options object to avoid making any 'obtrusive' changes to existing code.

I have this in 'production' use and it's working well.

FYI / for potential documentation purposes, etc -- the new API call currently returns 2 days worth of day ("today" and "yesterday"), with the following being an example of the JSON returned:

JSON Results from API Endpoint: https://gist.github.com/ArthurD/f688719e406a00db40f87a81f0592f87