Add maxLocalJobs to documentation.

[DailyDreaming]

Especially here: https://toil.readthedocs.io/en/latest/running/cliOptions.html . This should(?) be the correct way to push Toil to submit more jobs in a system like LSF (which is otherwise limited by cpu), but get context from the original PR first.

┆Issue is synchronized with this Jira Story ┆friendlyId: TOIL-768