Allow support for samples with multiple SNP allele variants

[ChrOertlin]

Description

We encountered a sample with multiple allele variants for a SNP ( REF/ALT --> G/T and G/A). Upon investigation of the BCF file we saw that it the reads were split almost 50-50 between A and T at that position. Currently, Genotype raises a valueError in such cases, which might happen again in the future.

Suggested solution

Pick one of the two or define it as a None call. In the latter case raising a flag with a statusDB entry (or similar) might be a good idea.

This can be closed when

A decision has been reached on how to proceed and the to be determined intended goals are reached.

Blocked by

None