Incorporate sbol-owl as git submodule

[bbartley]

Currently the turtle file is cherry picked from https://github.com/SynBioDex/sbol-owl3/blob/feature/sbolcomposition/sbolowl3.rdf

We should incorporate it as a git submodule to keep it synced.

[jakebeal]

Waiting until @goksel merges his branch into a release