Separate the improvements from the rmats 2 process implementation (rmats2, memory and cpus)

[cgpu]

For this contribution we would like to separate the 2 types of contributions in 2 single responsibility pull responsibility pull requests. https://github.com/TheJacksonLaboratory/splicing-pipelines-nf/pull/327

• [ ] Memory and cpu improvements
• [ ] rmats2 re-implementation