Allow multiple interpretations per VCEP

[wrightmw]

Once a VCEP has created their first interpretation associated with a variant, then they should provide a button to allow generation of a second interpretation.
This feature is not opening up the VCI to any number of interpretations per affiliation per variant, but only allows generation of other interpretations for the same variant by the same affiliation once the first record has been created.

Potentially allowing copying of information between interpretations on the same variant by the same affiliation is desirable, but this may be a V2 feature.

This ask was discussed on the Curation Tools Topic Call on 6/10/21. JIRA ticket: https://broadinstitute.atlassian.net/browse/CSP-172