Generalize keystorekey for non odsign use cases

Allow passing in variables like key location, alias, namespace,
and bootlevel.

Bug: 199914227
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.

Change-Id: I4da6c732e93e1b5a43ade89291d544b8bf92121b
Merged-In: I4da6c732e93e1b5a43ade89291d544b8bf92121b
7 files changed