New Requirements for PRR - Update

[sunnydean]

https://eoresults.esa.int/prr_collection_specifications.html

[sunnydean]

https://forum.apex.esa.int/t/new-stac-schema-for-dataset-ingestion-into-the-esa-prr/265/1

https://forum.apex.esa.int/t/reg-api-client-helper-script-for-prr-ingestion/262