Parse JSON-LD with digitalbazaar/pyld

Context

We need to parse JSON-LD files from the Web and local filesystems.

Alternative	Contra
Use rdflib's native JSON-LD parser	rdflib is planning to switch to pyld: rdflib/rdflib#2308
Use pyld via rdflib when rdflib does the transition	Will take some time, I suppose
Call pyld by hand and feed results → rdflib	∅

Decision

Call pyld by hand and feed results → rdflib

Consequences

• When rdflib switches to use pyld we will be able to simplify our code.