Support GRCH37 to 38 conversion

[kkrysiak]

We've had users request that we provide GRCH38 coordinates. So either a query that could find CIViC evidence using 38 coordinates as a query, or a CIViC converter that just supplies EIDs of interest with 38 coordinates annotated as well (potentially the whole dataset).

[ahwagner]

We intend to support this in a future version, we will also support queries by CA ids, and both types of query will operate through the allele registry for normalization to GRCh37, the CIViC standard.

[susannasiebert]

PR #73 add this functionality for single coordinate searches. It isn't yet supported for bulk coordinate searches.