7/n: Add HalClientMonitor

Adds HalClientMonitor and HAL-related things out of
BaseClientMonitor to HalClientMonitor.

This is mostly a rename, except BiometricScheduler, which adds
a tiny bit of code to handle HalClientMonitor vs BaseClientMonitor

Bug: 159667191
Test: atest com.android.server.biometrics
Test: No effect on devices
Change-Id: Iad79331eca956f8b854fa99a3f95cd21922d1bcc