Compatability with OpenEVSE WiFi V4.0.0+

[glynhudson]

Version V4.0.0+ of OpenEVSE WiFi firmware has changed control of the EVSE timer schedule from the OpenEVSE controller (RAPI commands) to the OpenEVSE WiFi.

V4.0.0+ WiFi firmware has been shipping on new units since March 2021.

It's important that the time schedule is not set via RAPI when running V4.0.0+ WiFi FW since this causes a race condition conflict. Here is the new HTTP POST schedule API Demand Shaper should use when setting the time schedule:

https://github.com/OpenEVSE/ESP32_WiFi_V4.x/blob/master/test/schedule.http

The version of the WiFi firmware can be found via /status output

RAPI commands will soon be disabled on the next release of controller firmware