Resolve TODO (util has been updated).
Removed the old housekeeping utility.

It is not worth updating this right now for cylc-6 as it has a known
major deficiency aside from assuming old-style cycle times - it can't
housekeep individual files below a cycle time labeled directory.
Address stop command stop point validation.
Removed broken manual test code.
Merge pull request #1041 from hjoliver/address-some-iso-todos

Address some iso todos