Update user restriction APIs to be called on parent instance

In the new COPE mode, some user restrictions should be applied globally
when called by the Work Profile PO.

Previously, the APIs addUserRestriction, clearUserRestriction and
getUserRestrictions did not support explicitly querying the parent
profile. This CL allows the WP DPC to now call these methods,
allowing the WP DPC to apply some restrictions globally.

This CL also introduces the enforcingUserId parameter to
setDevicePolicyUserRestriction. This new paramter is used as the
key of mDevicePolicyGlobalUserRestrictions and
mDevicePolicyLocalUserRestrictions.

Bug: 138709470
Test: Manual testing with testdpc
      atest com.android.server.devicepolicy.DevicePolicyManagerTest
      atest com.android.cts.devicepolicy.UserRestrictionsTest
      atest com.android.server.pm.UserRestrictionsUtilsTest
      atest com.android.cts.devicepolicy.OrgOwnedProfileOwnerTest#testUserRestrictionsSetOnParentAreNotPersisted
      atest com.android.cts.devicepolicy.OrgOwnedProfileOwnerTest#testDevicePolicyManagerParentSupport

Change-Id: Idfafd100bfcb250998a8628aba4cc378f1fc2c84