Add DPMS delegation scopes.

Implement the permission grant, package access, enable system app, and
keep uninstalled packages delegation scope APIs in the
DevicePolicyManagerService.

This feature gives a device owner or profile owner the ability to
delegate some of its privileges to another application.

Bug: 33105287, 33105284, 33105719
Test: cts-tradefed run cts-dev --module CtsDevicePolicyManagerTestCases --test com.android.cts.devicepolicy.MixedDeviceOwnerTest#testDelegation
Change-Id: I50d2903eb73ae7844ec1f6fe07e41101ea2760ea