Add SoC and range limits

[glynhudson]

Now SoC integration is implemented it, SoC limit feature can now be implemented. The easiest way is probably a dropdown box under the energy limit with a few presets e.g 60%, 70%, 80%, 90%

[kallisti5]

this would be nice... especially as a Bolt EV owner ;-)
Tired of hopping into the car to tune the charge limit.

[chris1howell]

Additionally a limit should be added for distance miles/km. Example... Charge to 300km range.

[pdhoogh]

@chris1howell : as range is from GOM (Guess-O-Meter), the charge too will be a guess. Depends totally on load, weather, style... results from the past do not guarantee similar results in future etc... so, what are you precisely looking for?

[KipK]

My 2 cents on this one. New Limit engine now handles time, energy, soc, and range.
#535

I still need to add it to the new gui.

[KipK]

Also added System Limits , persistant ones defined from config.
UI is all done, please give me your feedback on the UX.
latests builds are here ( files ending with gui_v2
https://github.com/OpenEVSE/ESP32_WiFi_V4.x/releases/tag/v2_gui
Enjoy :)