Make it possible to retain more than 50 seen sample IDs

[Jakob37]

Our users have been in situations where they found a pathogenic homozygous variant, and can see that it previously has been encountered.

The ideal would be to be able to see that specific variant (#115).

The backup is to manually look through the other cases to see which one carries the homozygot.

We encountered this situation and realized that as the max number of stored IDs is 50, that individual could not be found.

I guess that the 50 threshold is set for performance reasons. It would be great if a user could configure it to choose a higher value if needed.

[dnil]

Yes, the upserts and searches in arrays are a bit costly, but surely it is not an optimised number.