Rework activity manager debug dumps.

Change how we do debug dumps from the activity manager to make
everything go through the activity manager interface (no more
secondary interfaces), and use the command line arguments to
control what gets dumped.

The output from dumpsys without args still dumps everything.

When just dumping the activity service, we now dump a subset
of all of the am state that is interesting without being
overwhelming.

You can use "dumpsys activity -h" to get help with other things
that can be dumped.