Initialize new EnergyCoop when selecting group of GCs without running new yearSim

[GillisHommen]

-Instantiate EnergyCoop agent
-Make links to relevant agents (would normally happen during engine initialisation, now has to be taken care of manually)
-Gather data from all GCs
-Determine which KPIs/datasets/... can be filled without a new yearSim, write a function 'f_calculateKPIsWithoutYearsim()' that takes care of this.
-Ensure selecting any of the graphs doesn't lead to any errors, although some data will not be available without a yearsim.

-For the interface/results-UI: Make sure it is clear to the user which results are now being shown (area, company, collective, gridNode, ...)