Merged biological replicates

[ryanmboileau]

To whom it may concern the following is a suggestion that I brought up on the slack and we thought would be worth it to add to the repo.

In the current iteration of the pipeline there does not yet exist a step which merges bam files from different biological replicates (i.e. similar to the nf-core/ATAC pipeline). When converted to a bigwig a merged bam file with increased depth would be a better representation from which to heatmap when plotting consensus peaks in downstream analyses etc.

Best
Ryan