DPM API to enable or disable USB data signaling

Background
* The admin can disable signaling over USB on
  corporate owned devices

Changes
* Add DevicePolicyManager API to enable and
  disable USB data signaling.
* Add DevicePolicyManager API to test of this
  feature is supported.

Bug: 168301639
Test: atest com.android.server.devicepolicy.DevicePolicyManagerTest
      make RunSettingsLibRoboTests -j ROBOTEST_FILTER=EnableAdbPreferenceControllerTest
Change-Id: I1d2d71ec05a1565f58ffd691a66c68171a4f9b00
Merged-In: I1d2d71ec05a1565f58ffd691a66c68171a4f9b00