Overall code for APIs that exist so far

Bulk work for metadata auto APIs.

Still some work to do in future PR, but structure and overall code here.

Library here https://pypi.org/project/fso-metadata/ and test it in https://renkulab.io/gitlab/pauline.maury-laribiere/meatadata-auto/-/blob/class_apis/fso_metadata/examples.ipynb

@fabian.santi who should I add as reviewer ?