Add option to filter samples by max heterozygosity in advanced diplotype clustering

[alimanfoo]

When doing diplotype clustering we often are only interested in clusters with low heterzygosity because these are representative of swept haplotypes. So it might be useful to have a parameter in the advanced diplotype clustering function to remove samples above a certain threshold of heterozygosity.

[sanjaynagi]

how would you like to approach this?

1. Run the heterozygosity trace function before anything else, returning a list of samples passing threshold.
2. Pass those samples using sample_query to other functions?

Its a bit tricky because the het_bar function needs the dendrogram sample order, so we cant run this function before the dendrogram, but also, we don't want to run it twice.

[alimanfoo]

Hm, I forgot about the dendrogram. Maybe this is a bit harder than I imagined. Definitely would be better to avoid running anything twice if possible. Will have a think...