Add self test to rkp_factory_extraction_tool

Self test mode gets a test CSR and validates it.

Test: rkp_factory_extraction_tool --self_test
Test: atest VtsHalRemotelyProvisionedComponentTargetTest
Bug: 239839050
Change-Id: Ib4b0221ffcf56b60ded1ac2a1f85eddb77729cbf
3 files changed