Take advantage of the flexibility over multiple standing events

[jakobgemassmer]

Currently flexible charging is limited to one standing event, because the overall goal is to reach a desired_soc at the end of each standing event. The only way to bypass this is to set the desire_soc to 0, when generating the scenario.

For some strategies like e.g. balanced_market or schedule it would be great if multiple standing events would be taken into account. Simple example with only two standing events:

1. standing event = high prices
2. standing event = low prices

Check how much energy is needed to be able to make the next trip -> Charge nothing or only so much in the first standing event to be able to make that trip (don't charge to the desired_soc) -> make the trip -> charge more in the second standing event.

If the prices are lower in the first standing event, a vehicle could charge enough to make the next to trips, so it doesn't need to charge in the second standing event (when prices are higher there).

Maybe we can introduce a new flag like flex_over_multiple_standing_events = True