Move keymint utils to a library.

Also, delete unused libkeymasterfiles.

Ignore-AOSP-First: No merge path from AOSP
Bug: 177729159
Test: mmm system/keymaster
Merged-In: Id8ec7e46d766fa985cebaee00d7a22687c457029
Change-Id: Id8ec7e46d766fa985cebaee00d7a22687c457029
2 files changed