GBFS support

[pablohoch]

Needs motis-project/osr#20

Example config:

gbfs:
  feeds:
    # GBFS feed:
    #callabike:
    #  url: https://api.mobidata-bw.de/sharing/gbfs/callabike/gbfs
    # GBFS manifest / Lamassu feed:
    mobidata-bw:
      url: https://api.mobidata-bw.de/sharing/gbfs/v3/manifest.json
  default_restrictions:
    mobidata-bw:callabike: # "callabike" feed contained in the "mobidata-bw" manifest
      # these restrictions apply outside of the defined geofencing zones if the feed doesn't contain global rules
      ride_end_allowed: false
      ride_through_allowed: false
    #mobidata-bw: # default restrictions for all feeds contained in the "mobidata-bw" manifest
    #callabike: # default restrictions for standalone GBFS feed "callabike" (when not using the mobidata-bw example)
  update_interval: 300
  http_timeout: 10