Implement an early prototype for multi-user management device enrollment

Flag: android.app.admin.flags.multi_user_management_device_provisioning
Test: atest CtsDevicePolicyTestCases:android.devicepolicy.cts.ProvisioningTest
Bug: 390162247
API-Coverage-Bug: 442780973
Change-Id: Id267fd1a50d1001754119a2a5d34ef51f561d371