Gas, sector coupling and electrical clustering can not be run independently

[CarlosEpia]

When using spatial clustering, the argument args["network_clustering"]["active"] decides if the electrical AND gas clustering are activated. Therefore it is not possible to use one of them independently. In addition, the sector clustering has its own "active" parameter in the args, but it is only executed when the gas clustering is used.

There is a dirty provisional solution for using gas clustering alone. Set args["network_clustering"]["active"] = False initially and change it after the electrical clustering is skipped and before calling the gas clustering:

etrago.spatial_clustering()
etrago.buses_by_country()
etrago.geolocation_buses()
args["network_clustering"]["active"] = True
etrago.spatial_clustering_gas()