Update sbatch to be more detailed for newer users

[mckenziephagen]

Update to sbatch for MRIQC protocol paper.

There are new, more verbose comments to assist those who are less familiar with bash/sbatch/HPCs.

@oesteban

[welcome]

Thanks for opening this pull request and congratulations for taking it to the finish line! It looks like this is your first time contributing to MRIQC. 😄
We invite you to list yourself as an MRIQC contributor. To learn more about what that entails and how we credit our contributors, please check out the contributing guidelines. If your name is not already on the list, please insert it, in alphabetical order of (i) lastname and (ii) firstname, into the .maint/CONTRIBUTORS.md file.
Of course, if you want to opt-out this time, there is no problem at all with adding your name later. You will be always welcome to add it in the future whenever you feel it should be listed.