Stop LockSettingsService from calling DevicePolicyManager directly

This is a violation of layering (LSS is considered a lower level
component than DPM) and source of deadlock due to lock inversion.
This change tries to remove most of the direct calls into DPM from
LSS. After this, there will only be a handful non-critical invocations
remaining:
1. DPM.reportPasswordChanged()
   This is always called on a handler thread so it's OK (LSS does not
   hold any hold while calling out). Consider this as a (asynchronous)
   broadcast.
2. DPMi.reportSeparateProfileChallengeChanged()
   This is now moved to the handler thread, similar to
   DPM.reportPasswordChanged().
3. DPMi.canUserHaveUntrustedCredentialReset()
   This is still a violation but it will soon be removed as we
   remove the caching of syhnthetic password alltogether (deprecating
   old resetPassword()). So I'll leave it for now.

Test: atest com.android.server.locksettings
Test: atest com.android.server.devicepolicy.DevicePolicyManagerTest
Test: atest MixedManagedProfileOwnerTest#testResetPasswordWithToken
Test: atest MixedDeviceOwnerTest#testResetPasswordWithToken
Bug: 37090873
Bug: 141537958
Change-Id: Ie44cb418ab255bd016c5dd448674beabd362b74c