[SFS] Allow upper-level hirarchy for CRF-sectors when selecting CRF-sector division

EDIT by @stap-m:
This issue is relatively old but not fully solved. Specific requirements on the implementation are documented in my comment below https://github.com/OpenEnergyPlatform/oeplatform/issues/1523#issuecomment-1865952983

Description of the issue

Selecting CRF sector division in field S7 one is confronted with a myriad of individuals of CRF sectors in the ontology which is far to detailed for most of the users.

and from issue https://github.com/OpenEnergyPlatform/oeplatform/issues/1524 (now also adressed here)
If you choose a predifined sector division, say KSG, then only KSG sectors should show up und field: "Which sectors are considered in the study?". This function has been before, but seems to have vanished.

Ideas of solution

https://github.com/OpenEnergyPlatform/oeplatform/issues/1523#issuecomment-1865952983