Profile Owner API to clear application data

This new API lets DOs clear application data on a per package basis. It
can be used to reset misbehaving packages as well as for a light-weight
session model where employees log in to a device and have their data
cleared when they log out.

Test: cts-tradefed run singleCommand cts -m DevicePolicyManager --test
com.android.cts.devicepolicy.DeviceOwnerTest#testClearApplicationData
--abi arm64-v8a
Bug: 63910199
Change-Id: I6a03ae90fffe6159172ea7e46f9b8b69efeabcfe