Ability to DELETE jobs and datasets

[julienledem]

When jobs or datasets are deleted (or renamed) we need a way to tell Marquez that they don't exist anymore so that they don't clutter the lineage view.
It would make sense to have DELETE support on /api/v1/namespaces/{ns}/datasets/{name} and /api/v1/namespaces/{ns}/jobs/{name} resources.
This is a soft delete in the internal marquez model. It creates a new deleted version. The resources will not show up in the "current" lineage view in GET /api/v1/lineage

[julienledem]

also see #754

[mobuchowski]

Done in #2032