Parallelism workshop data

[IAlibay]

The tpr/xtc files used for the parallelism part of the workshop are not available in this repo (due to their large size).

As a result of this, the workshop materials as-is cannot be used by others.

Whilst a shortened tpr/xtc were provided, it's not clear to me if those are the final versions that should be used, so I'm raising this issue to discuss this.

1. Should we switch the contents to use the shortened version of the tpr/xtc?
2. Or should a larger version of the files be uploaded to MDAnalysisData?

Note: we need to resolve this before we can release 1.1.0.

[IAlibay]

pinging @mnmelo

[orbeckst]

@mnmelo I added a reminder issue for you to add the missing data set to MDAnalysisData MDAnalysis/MDAnalysisData#47