Add escrow token API in DevicePolicyManager.

Take advantage of the new authentication flow in LockSettingsService
and allow PO or DO to provision escrow tokens on the device. The
escrow token grants them the ability to change device lockscreen
(if used by DO) or work profile challenge (if used by PO). The
new password reset mechanism is even usable before user unlocks,
and it preserves authentication-bound keys in keystore.

Test: runtest frameworks-services -c com.android.server.SyntheticPasswordTests
Test: runtest frameworks-services -c com.android.server.devicepolicy.DevicePolicyManagerTest
Test: cts-tradefed run cts-dev -m CtsDevicePolicyManagerTestCases -t com.android.cts.devicepolicy.MixedDeviceOwnerTest#testResetPasswordWithToken
Bug: 33126620
Change-Id: Iaa684c51946f726cbd909e9ac70ad3e9ca3de1ac