Accessibility map: Add a parameter to limit the number of transfers

[tibobliss]

It can be very useful to know how far one can go within a given time AND using no more than a given number of transfers.

For instance, to calculate the direct accessibility (0 transfers) to a new heavy rail project.

[davidmurray]

I support this.

For example, here is what is available in Netplan:

[greenscientist]

We will need to first add a new parameter to the TrRouting API to limit this number of transfers.