Add HsuDeviceProvisioner

HsuDeviceProvisioner class is added to segregate device provisioning related
logic which will be called in HsumBootUserInitializer.In this cl I am
just adding the new class definition with the prupose of eventually
moving the device provisioning logic from HsumBootUserInitializer to
here.

Test: atest FrameworksMockingServicesTests:HsumBootUserInitializerTest
Flag: android.multiuser.hsu_device_provisioner
Bug: 424203846
Change-Id: Ib153a5b9cda11a8b76d6cb20efb879d460a32cf4