Quick start of main README.md should include the main use first

- Include workflow image
- Check flow of README

About RNA-Seq pipeline:

- Replace GSE93717/v109 references with GSE129146/v115
- Explain how users add new KO/OE FASTQs under data/experiments/raw/<dataset>/., Explain copying/editing a config per experiment. (work with @sgiannouk for that)
- Fix new example config labels/typos.