[FEATURE REQUEST] add ability to discover collections of dataset

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.