Keep only service binding in DataLoaderManager.

This simplifies:
- resource management - no extra copies of controls,
- state management - all states in one place, no more hidden (bound but
not created) state.

Bug: b/153874006
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest IncrementalServiceTest
Change-Id: I3d16a099c7f42fcf14637c5a8e96bd6f99e073d1