Add support for rsID queries

[gromdimon]

Is your feature request related to a problem? Please describe.
Currently REEV supports strict HGSV notation, gnomAD, or SPDI-style of sequence variants. However, some labs use rsIDs, which we should support as well.

Describe the solution you'd like
Add support for rsIDs queries in search.

Describe alternatives you've considered
N/A

Additional context
N/A

[holtgrewe]

Annonars already has a mapping from dbsnp ID to coordinate. Also a mapping from clinvar ID to coordinate. That is, the data is there.

However, we don't have an endpoint yet.