Let system_server writes to dumpstate.options property.

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: I7ebbb7ce6a0fd3588baca6fd76653f87367ed0e5