[Feature] Clustering of Emitters

Originally from thg-tuda/bp/greenhouse-gas-balancing-tuda-frontend#45

Summary

Is should be possible to cluster emitters? --> e.g. Treibstoffe Fahrzeuge = SUMME(Fahrzeuge Benzin + Fahrzeuge Diesel + LNG Fahrzeuge)

What is the added value of this feature

• Better Overview for big Balances
• More detailed listing of emissions caused

UI-Mockups, Prototypes, Vision

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