Update ClinVar pipeline for new XML format

[rileyhgrant]

Resolves #1569

• Updates the ClinVar pipeline's XML parsing step to parse the new ClinVar XML format
• Minor edits to accomodate ClinVar updates
  • On the frontend, renames ClinVar's 'Clinical significance" to "germline classification", following ClinVar's change in terminology
  • Adds entries to the Gold Star mapping dictionary to accomodate new terminology
• Bumps Hail to 0.2.128 to allow for VEPing of GRCh37 varints using Hail's built in convenience function
• Still includes the commented out Aliases for ClinVar indices along with a "TODO:" comment. Following the practice of several previous PRs, temporarily specifying an index, rather than an alias, in this PR will allow for an easy rollback if needed. Once this proves stable in production, another PR will go back to using the aliases

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Screenshots of a local browser and API querying an indice in the production ES cluster that uses data from the output of this PR:

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[phildarnowsky-broad]

Good stuff overall, I did spot some things, mainly legacy stuff that we should take this opportunity to clean up.

[rileyhgrant]

Heya @phildarnowsky-broad, thanks for the review.

I believe I've addressed all the comments, with one new fixup commit per comment. I've tagged you for re-review, at your convenience.

[phildarnowsky-broad]

Good to go, nice work