Switch to new resource monitor snapshots

[matz-e]

As per meeting of Oct 05, 2017, we should replace our own accounting with the new snapshots feature of WQ.

TODO for documentation/draft:

• Find WQ documentation about this
• Add more to the TODO list below

Things to be implemented

• Setup on the master
  • Add get_resource_monitor_setup method to the workflow
  • Pass setup here back to the "main loop"
  • Take setup and mangle it, add to the actual task object
• Adapt worker wrapper.sh
  • Replace wrapper start with WQ trigger
  • Replace wrapper end with WQ trigger
• Adapt worker task.py
  • Remove wrapper time extraction
  • Remove CMSSW log time extraction
  • Remove time data stubs
  • Replace all mentions of task_timing with WQ triggers
• Collection on the master
  • Add bits to the Task class here
  • Delete old definitions
  • Add bits about resource usage at each snapshot (advanced)
• Plotting
  • Nothing for straight-up replacement
  • Plot bits about resource usage at each snapshot (advanced)

[matz-e]

Not sure if updates trigger notifications… I filled out more of the list of stuff needing to be done.