Incorporate GBFS as recommendation for bike sharing standard

[brylie]

The General Bike Feed Specification is an industry standard for bike sharing organizations. As it is already established, we can/should adopt it as a recommendation. This is in our spirit of building on and aligning with existing standards.

https://github.com/NABSA/gbfs

[brylie]

It is also worth noting that the City of Los Angeles Mobility Specification is also built on the GBFS specification.