Add timeframe controller to reach specified SoC in specified time frame

[Femumme]

This PR adds a new controller that allows the user to easily set a specified timeframe to reach a target SoC.

The main use-case for this is to sell during expensive times and charge during low-cost times. I'm planning on adding an automatic mode as well, that uses a TimeOfUse Tarif to determine the most cost effective hours to charge / discharge.

Any feedback is welcome! Since this is my first contribution, I'm also happy to receive any advice what I could've done better :-)