Use a system property to define extra command-line arguments.

Currently, we define 4 hardcoded init services to launch dumpstate with
different command-line options (since dumpstate must be launched by
root):

- bugreport
- bugreportplus
- bugreportwear
- bugreportremote

This approach does not scale well; a better option is to have just one
service, and let the framework pass the extra arguments through a system
property.

BUG: 31649719

Test: manual

Change-Id: I537775a7c8ea4ab04dbdaaf2bb2f513cc29f966b