Needed here to enable submitting the equivalent fix in AOSP.
Generalize keystorekey for non odsign use cases
Allow passing in variables like key location, alias, namespace,
and bootlevel.
Bug: 199914227
Ignore-AOSP-First: Cherry-pick to fix merge conflict with security fix.
Test: Boot device, verify that key is created, and artifacts are signed
by odsign. Reboot verify that the key is validated and artifacts are not
resigned.
(cherry picked from commit 2bc6196960e467467321267357e3e8f3a5feb6d8)
Merged-In:I4da6c732e93e1b5a43ade89291d544b8bf92121b
Change-Id: I3915f04d15b4d32ca7d6ecebbd5cd7754960b894