Add filtering step to remove effects from BCR/TCR genes

[TimothySundell]

Hi,

Just want to start by saying, what a fantastic tool! Incredible :)

I was looking around the docs for a way to filter out unwanted genes before running PCA and unsupervised clustering, particularly for B-cell receptor and T-cell receptor genes, as these have been shown to interfere with finding biologically relevant clusters in datasets of B and T cells.
My suggestion is to add a checkbox for the removal of BCR/TCR genes, as manual gene name entry is excruciating due to the sheer number of genes. For now, we have been doing the filtering just by using Regex.

If you are interested, please give a look at our paper investigating the issue: https://doi.org/10.1093/bfgp/elac044.