Demultiplex by I1

Modify bcl2fastq for additional I1 demultiplexing if needed (optional, Annique needs it for her data)

changed milestone to %RNA preprocessing + QC

added High priority label

assigned to @carnold

Implemented. Waiting for an example dataset to fully test it.

The feature is still in its own, unmerged branch. To be merged and tested when we have another dataset where we need this.

removed High priority label

added Low priority New feature labels