Make transport networks (de)selectable (optionnally visible/considered)

[ghost]

Is your feature request related to a problem? Please describe.
Only one possibility at present: produce a shriveled map with exactly the modes present in the input files

Describe the solution you'd like
this possibility would allow for producing different states of the model with different sets of modes by deselecting one or more mode of transport modes/networks.
This new selection should

• UI
• remove from the representation the deselected transport modes, id est all the networks of these deselected transport modes
• do NOT allow to deselect the (mandatory) road mode
• potentially alter "vmax" if e.g. airplanes are deselected
• alter the legend accordingly
• alter the exported file

Describe alternatives you've considered
This would be more convenient than preparing a full new dataset