Add spec to check whether application and final_demand groups return same CO2

[michieldenhaan]

I.e. V(G(final_demand_group), G(energy_export), primary_co2_emission).sum - V(G(application_group), primary_co2_emission).sum should be zero.

This ensures that all final demand / export has an application.

CO2 data can only be downloaded in the "Application primary and final demands" CSV, which includes all nodes in the application_group. The CO2 shown there should be MECE.

Edit: same should hold for primary_demand