Function to retrieve the schema_id of a type

[crisely09]

The idea came up when I tried to find the right schema_id for annotations, as when I tried to use the id I could get from the annotation schema definition in Fusion, i.e. https://neuroshapes.org/commons/annotation, but it gave an error. The correct schema_id was: https://neuroshapes.org/dash/annotation, that can be also given as datashapes:annotation. This is why it would be good to have a function that provides the correct schema_id.