Implement adjustments based on data validation

[ClaraBuettner]

Many things regarding this issue were already implemented. Feel free to add them here or use it as a space to list, what needs to be decided or is still in progress.

[CarlosEpia]

@IsGut and @pl0via in this issue we can discuss everything related to scenario validation. Since the first version of eGon100RE is coming at the end of this month, I would like to ask you if there are additional comments regarding the status2019 scenario, or if something already mentioned does not match the common expectations yet.