Work on issue #28942589: Tune job scheduler

We now have a new settings key that provides all of the existing
tuning parameters, plus some newly redone ones for dealing with
different memory levels.

Changed the minimum batching for overall jobs from 2 to 1, so
we will never get in the way of immediately scheduling jobs
when the developer asks for this.  We should now be able to rely
on the doze modes to do better batching of jobs for us when it
is really important.

Also work on issue #28981330: Excessive JobScheduler wakeup alarms.
Use a work source with scheduled alarms to blame them on the app
whose job they are being scheduled for, and add a check for whether
a job's timing constraint has been satisfied before considering it
a possible candidate for the next alarm.  (If it is satisified,
the time is in the past, so we should not schedule an alarm for it.)

Finally clean up a bunch of the dumpsys output to make it easier
to understand.

Change-Id: I06cf2c1310448f47cf386f393e9b267335fabaeb