Draft: CI: maintenance/stability fixes
- 5G RFsim: Start core/RAN in parallel, where possible
- 5G RFsim: Wait for UE IP address before continuing with ping
- Accelleran F1-Interop: Start DU/UE in parallel
- Always switch off idefix UE after test
- 5G RFsim: on startup, force docker volume removal to suppress warning