Switch from `normalization` to `rdf-canon` test suite

[BigBlueHat]

Handled in #182

[mielvds]

@BigBlueHat @anatoly-scherbakov Why is the rdf-canon work included in this project? What's the link with json-ld? Honestly don't know :)

Since this dependency was introduced, the rdf-canon work has moved from CG to WG. The spec is now an official recommendation and published at https://www.w3.org/TR/rdf-canon/. The test-suite at https://w3c.github.io/rdf-canon/tests/

[anatoly-scherbakov]

I remember there was a verbal discussion about it, but I do not recall any of the details :(

[mielvds]

@davidlehn do you recall? :)

[davidlehn]

Roughly speaking, the original JSON-LD specs had a "normalization" algorithm section and API. At some point it was realized that part had value for the wider RDF ecosystem and could be developed on its own. And it was split out, renamed to canonicalization, and got its own group and specs. jsonld.js also split the code out into its own rdf-canonize library. pyld may want to do something similar. We use that API all the time for digital signatures and similar so has been useful to keep the interface around and tested. Although that's probably not totally needed.

[mielvds]

Thx for the clarification @davidlehn; continuing discussion in #220