Added APIs diagram

Author: schnuerle

README.md

@@ -71,6 +71,10 @@ Many parts of the MDS definitions and APIs align across each other. In these cas
 
 You can read more in our **[Understanding the different MDS APIs](https://github.com/openmobilityfoundation/governance/blob/main/technical/Understanding-MDS-APIs.md)** guide. 
 
+![MDS APIs and Endpoints](https://i.imgur.com/L5s927a.png)
+
+### GBFS Requirement
+
 All MDS compatible feeds [must also expose](/provider/README.md#gbfs) a public [GBFS](https://github.com/NABSA/gbfs) feed. Compatibility with [GBFS 2.0](https://github.com/NABSA/gbfs/blob/v2.0/gbfs.md) or greater is advised due to privacy concerns and support for micromobility. See our [MDS Vehicles Guide](https://github.com/openmobilityfoundation/mobility-data-specification/wiki/MDS-Vehicles) for how Provider `/vehicles` can be used by regulators instead of GBFS `/free_bike_status`. Additional information on MDS and GBFS can be found in this [guidance document](https://github.com/openmobilityfoundation/governance/blob/main/technical/GBFS_and_MDS.md).
 
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