Add a SHACL example

[klinovp]

I.e. adding constraints, some data, consuming validation report, etc.

[HolgerKnublauch]

On https://github.com/stardog-union/stardog-examples/blob/develop/examples/api/data/music_shacl.ttl

sh:Shape shouldn't be instantiated directly - I guess you meant sh:NodeShape?

FWIW, as a naming convention for property shapes we try to use NodeShapeURI-localNameOfProperty, so for example ex:AlbumShape-date instead of ex:AlbumDateShape.