export all-sample counts table

[kew24]

In my implementation of the DESeq2 Rmd steps, I've separated things out by comparison. This means that each comparison exports counts & vst matrices for the samples w/in this comparison; however, there is no global matrix exported with all samples. To implement this, two options come to mind:

1. this could be it's own short independent rule, or
2. we could rework the entire DESeq2 rule to go back to a one-Rmd approach (just lapplying through each comparison, as Kin originally had it, iirc)

Creating this issue so we implement this eventually, regardless of which route we choose.