DO NOT MERGE: Change verity key formats

Change boot, recovery, and verity metadata signing keys to use the
same PKCS8 / X.509 PEM format as the other signing keys, and update
build scripts to use correct arguments for the updated signing

Bug: 15984840
Bug: 18120110
Change-Id: I23ed5a004ecdad6cf7696487935ad5031eb8adf8
(cherry picked from commit 72d90eb1895932343586717daa1865019473b2f5)
7 files changed