Ability to load RDF files (not AWS bulk loader, not SPARQL update queries)

**Is your feature request related to a problem? Please describe.**
I have a set of RDF files in Turtle. I connect to a local GraphDB instance, not to Neptune. It seems that the `%seed` command can only work with INSERT queries, while the `%load` command is specific to Neptune bulk loader.

**Describe the solution you'd like**
I would like to be able to load the Turtle files from the notebook. Basically I want to be able to share notebooks with their associated data included in RDF files, so that those to whom I send the notebook can load them in one click.