Use java-jsonld for JSON-LD support

Currently Apache Stanbol uses an outdated implementation for JSON-LD (see STANBOL-220) that is no longer confirm with the specification.

The java-jsonld library provides a default implementation for JSON-LD for java. This is already used by Sesame and Jena.

While their is also an integration with Clerezza this is incomplete in the current version. Because of this this will use the following migration path:

1. repurpose the o.a.stanbol.commons.jsonld module so that it uses java-jsonld instead of its own implemetnation.
   • remove the old outdated code
   • add Clerezza ParsingProvider and SerializingProvider for JSON-LD
2. Contribute the ParsingProvider and SerializingProvider to the json-ld project
   • as soon as they accept and release the contribution the o.a.stanbol.commons.jsonld will be removed.
3. Adapt the whole JSON-LD Clerezza support to the new Clerezza 1.0.0 API and make it a direct part of Clerezza (similar as it was done for Sesame and Jena)