Add the compos_key_helper domain for the process which has access to
the signing key, make sure it can't be crashdumped. Also extend that
protection to diced & its HAL.
Rename compos_verify_key to compos_verify, because it doesn't verify
keys any more.
Move exec types used by Microdroid to file.te in the host rather than
their own dedicated files.
Bug: 218494522
Test: atest CompOsSigningHostTest CompOsDenialHostTest
Change-Id: I942667355d8ce29b3a9eb093e0b9c4f6ee0df6c1
