Support cloud/remote service based database id lookup

[jblachly]

Would like to support remote service based database id lookup.

Problem/Rationale: Doing database lookups from disk can be a very time-consuming portion of the mucor run. Loading all databases into memory would be intractible.

Proposed solution: Make RPC (e.g. a REST service)

Ensembl VEP is not suitable because it works only for coordinates in current build.

We are building wtv - What's that Variant as a microservice to do database id lookups.