Map csvw:TableSchema and RML

[VladimirAlexiev]

https://kg-construct.github.io/rml-io/spec/docs/#logical-source-in-rml uses CSVW but only to describe the location and dialect of a Table.
In a dataspace scenario we use TableSchema to describe some csv, to then provision ingest to a timeseries database, while enabling discovery and other semantic integration approaches.
CSVW is a nice focused spec dedicated to CSV semantic description, so I think it's worth examining it, mapping it to RML, and maybe finding some features to add to RML.

The CSVW Manufest is JSON (also JSON-LD) and it has one "defect": it maps columns not to RDF props but to URL templates. So maybe we should retool to use RML instead of CSVW.