Exposing flickerlib classes and layer tracing to sysui

- Allow recents component to enable/disable layer tracing
- Expose flickerlib classes for use with sysui/launcher tests
- Allow trace files to be moved to a path that the client can read
- Ensure layers are flattened with depth traversal to encode ordering

Bug: 140244969
Test: atest FlickerTests
Change-Id: Ia0934ec7c2b9484fa6c85f5aa8d9b2e5e6f7dc0f