Clean up WQ stats:
1. add new information on tasks (cancelled), workers (joined, idle), reported
resources (bandwidth, memory, etc) to WQ stats.
2. reorganize and group related fields in stats structure.
3. reorganize the format of the log so related fields are grouped together.
4. remove the printing of deprecated fields in the log.
Report total_tasks_cancelled, total_workers_joined, and workers_idle to the
catalog.