Warn users about disk usage prior to each run.

[DailyDreaming]

Wherever they set the jobstore, if it's local, we can have a user warning telling people how much disk space they have left.

┆Issue is synchronized with this Jira Task
┆Issue Number: TOIL-837

[diekhans]

Wherever they set the jobstore, if it's local, we can have a user warning telling people how much disk space they have left.

This comes out running out of /tmp space because of Toil leaving tmp files behind. Users tend to assume that is it someone else consuming the disk space, so just saying how much disk space is left is of limited use. It would be far more helpful to print out the about of space that the run has consumed, both final data files and tmp files that were not cleaned.

[DailyDreaming]

@diekhans Hmmm... actually tracking the tmp dir usage would be useful. I'll look into it.