Update Concept and Scheme models

[johnatawnclementawn]

Resolves #123

This will break the test data - the RDM -> Lingo migration will need to be re-run, and likely updated based on new model configurations.

[robgaston]

lgtm! thanks!

[johnatawnclementawn]

1. load AFS thesaurus
2. start celery (I use python -m celery -A arches_lingo worker -l info)
3. Run RDM to Lingo ETL module for AAT Entries http://localhost:8000/plugins/bulk-data-manager
4. Verify number of part_of_scheme tiles created matches the number of concept resources created

[jacobtylerwalls]

+1 tested. Few things noticed along the way that can be follow-ups:

• make etl_modules an explicit package, so that it's measured by coverage
• use CommandError
• catch CommandError and surface the error message in the GUI, but may want to check with @chiatt

[johnatawnclementawn]

@robgaston coverage was previously passing because Lingo ETL Modules was not a package. Given the blocking nature of these model changes for other work in flight, I created a follow-up issue #131. Would you like to see that addressed in this PR or okay to do the follow up?

[robgaston]

@johnatawnclementawn it's fine to address the coverage in the follow up ticket