Documentation: Replace NoMachine with HPC OnDemand #231
Description
On https://hpc.nih.gov/docs/nx.html, it says "NoMachine will be retired on August 7th, 2025. After August 7th, NoMachine will no longer be available to Biowulf and Helix users."
On this page: https://ccbr.github.io/RENEE/latest/RNA-seq/gui/#4-special-instructions-regarding-x11-window-system, Section 4, we should replace the NoMachine instuctions with HPC OnDemand instructions for X11.
