Metadata Management Integration - Metadata Access Implementation

As a continuation of SP-3500

 implementation (if needed) of server API signature and implementation (or provision) of a client library able to talk to this server implementation and examples description

This client library (e.g. in python) could be used by other client applications to invoke the data access interface or to better understand the server implementation

Client library could be inspired by other metadata access libraries present into the astroquery module

https://astroquery.readthedocs.io/en/latest/

Likely Magenta to lead