Enable SYSTEM_TRUSTED_KEYS and add certification for x509 signing for system. CRs-Fixed: 1116507 Change-Id: I01298d75da0ff9faee2d01118107d53e9a2aef8a Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org> Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>