Update GSVA analysis and figure

[sjspielman]

Closes #1337

This PR updates the GSVA analysis and associated manuscript figure.

The analysis itself is updated to consider cancer_group instead of display_group, and associated results as well as README are updated accordingly. Re-running this module also updated some of the retained results because the module hadn't been run with the most recent data. There's a teeny bit of unneeded updates -

• Only do a notebook, not notebook + knitted HTML
• Removed very unneeded lines here
• Added more code chunk labels since the notebook was rendered with repeated chunks unless all chunks were labeled. No idea why, but it's rendered at least.

The figure script is updated to output a new GSVA heatmap with a cancer_group annotation as well as an associated legend. The final plot will therefore have separate legends for A and B.

Question: Do we want to remove "Other" from the heatmap, or keep it at the end (as is currently there)?

[jharenza]

Question: Do we want to remove "Other" from the heatmap, or keep it at the end (as is currently there)?

We can remove other - those results won't be super meaningful!

[jharenza]

going to merge and update manuscript results based on this