[FEATURE REQUEST] add ability to discover collections of dataset

[fcomte]

We should try to read metadata file in standards format.
As a first try we should read collection of datasets as json-ld dcat.

• show a list of dataset based on an url input
• redirect the user to the data explorer (if possible) to read distributions of this datasets
• ability to share / save collections for the user or a group if user

This first exploratory step will not involve publish dcat file for dataset "inside onyxia , file explorer" , dcat file will be only on http as a first step also.