[automerger skipped] Move keymint utils to a library. am: 77b9c31d86 -s ours

am skip reason: Merged-In Id8ec7e46d766fa985cebaee00d7a22687c457029 with SHA-1 19d8dd2d7a is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/keymaster/+/14644996

Change-Id: I765f4e65ff557ed6d35b616c91ad1a03c58ce455