TrigT1RPChardware: remove DISP_ macros

Replace the usage of DISP macros for messaging as appropriate:

• pass MsgStream for useful messages
• plain cout for standalone/validation code
• throw exception for fatal errors
• comment code if only needed for debugging

Also delete methods that were marked as obsolete.

Relates to ATLASRECTS-6313.

👋 Note to shifter: This codebase and its coding style is ancient. Lots could be improved but this is beyond this MR.