Make GBFS optional for some modes

[schnuerle]

Is your feature request related to a problem? Please describe.

With the forthcoming addition of new modes like carshare, passenger services, and delivery robots in 2.0, we should consider relaxing the GBFS requirement on all modes in all circumstances/jurisdictions. For example, since delivery robots are not directly reservable by customers, they should not be in any kind of public GBFS feed.

Describe the solution you'd like

Change the GBFS Requirement to be more optional for some modes (maybe even list which modes and scenarios it applies to). Note it should certainly still be required for bike and scooter share.

Is this a breaking change

• No, not breaking

Impacted Spec

For which spec is this feature being requested?

• provider

Describe alternatives you've considered

N/A

Additional context

We have gotten some questions about this already with regards to new modes, so I want to address it now and be clear.