Adding CA-based skeleton file for FastChain, adding a new test, remove old files
- Adding new file for FastChain skeleton in CA-based (To be used w/ and w/o Overlay)
- Update FastChain trf script for this new file
- Remove two old overlay tests
- Add a new overlay test doing comparison between legacy vs CA-based script
- This MR replaces !56222 (closed) (closed)