API to set managed subscriptions policy

These APIs would be used to set/get managed subscriptions policy.
Managed subscriptions policy can be used to associate SIM/subscription
with managed profile.Such that all call/messages would only go through
managed profile for the managed SIM/subscriptions.

Bug: 258821753, 258628704
Test: atest android.devicepolicy.cts.ManagedSubscriptionsPolicyTest
Change-Id: Ie6eb3757ffd48dc383148ffb0d02b6884e92480f