DO NOT MERGE: NIAP: Use keystore to encrypt KEY

Encrypt Classic and LE key via kerstore.

Bug: 140483038
Test: Manual
- Pair a device after OOBE
- adb shell settings put global niap_mode 1
- Re-enable Bluetooth
- Ensured that the Key was read correctly
- Ensured that the Key was encrypted when stored on disk

Change-Id: I6ece990135fb0a16eef3ecf6508ca759eee2c4c6