Add support for protein coordinates

[ahwagner]

This issue is to add backend support for our first targeted class of categorical variants under the Cat-VRS spec.

Categorical variants representing protein sequence consequences (e.g. BRAF V600E) require defined protein sequence coordinates and protein sequence state at those coordinates. This can be inferred for many CIViC variants already by VICC Variation Normalization service.

In CIViC meeting today (12/12/2024) we discussed adding a protein variant details table to the CIViC backend that captures the necessary information for representing Protein Sequence Consequence data, and subsequently making this accessible to CIViCpy caches for use in our GKS submission efforts.

This issue tracks progress to create that protein coordinates table and populate it.

Tagging @susannasiebert @acoffman and @korikuzma to help define requirements.