Add support for RDF collections

[karelklima]

LDkit could support collections for greater benefits of developers.

Prerequisites:

• Standardized collection format
• Support for collections within SPARQL query

[ddeboer]

Ah yes, I seem to need this for querying SHACL files that contain sh:or, which takes an rdf:List. Are there workarounds for this or do we need fully-fledged support for RDF collections in LDKit?

[karelklima]

I am not aware of any workarounds at the moment, but at the same time I have never tried too hard to find any. As far as I know there is no (reasonable) way to query rdf:List in SPARQL, therefore there is no way to implement it in LDkit now without substantially rethinking the whole design of the library.

For SHACL files content, I would use for another library - perhaps LDflex, which supports collections.