Implement Pii Stripper Part 3

The incident request args sets privacy spec. Strip action is optimized
to run once for each type of spec and ready for flush multiple times.
Incident command is updated to take -p option to specify privacy spec.

Bug: 64687253
Test: unit tests written, manually run incident command to test as well
Change-Id: I6753df117f76dc1a5f4d2152baa3fbbf56b490e4