fix/duplicate-uuid

[Avantol13]

• Handle issue where a graph node gets created with a UUID that already exists in the graph under a different node type
• When determining if a UUID is valid for the graph:
  • if uuid already exists, make sure it's the same type as the submission (in which case we'd be updating)
  • if uuid already exists and the submission is a different type, we should NOT allow creation
• added regression test
• Additionally, fix an issue with the image build failling because of pip 10 being released

pip 10 fix: pypa/pip#5221 (comment)

TODO fix internal error when submitting same thing but changing submitter id

[philloooo]

stale