This fixes a bad data output when prereq prerequireds break

Fix #15463 Fix #15331
Add __run_num__ and __sls__ to prereq failure condition

In addition add some comments to hopefully explain what we are doing
Add ProcessManager for salt internals
Change netapi to use processmanager
Change main master daemon to use ProcessManager
Add tests for processmanager
Change master ReqServer to also use a processmanager
Name the Reqserver processManager
Pylint cleanup
More pylint
Add _clear_old_jobs to processmanager

In addition set names for MWorkerQueue and _clear_old_jobs processes
Merge pull request #15568 from jacksontj/process_manage

Process manager