Add athena accessor to the menu

Adds access methods to call the trigger configuration from within athena The methods get the menu source from the job setup and provide the configuration using the functions provided in !31782 (merged)

This has been tested for file access, which is currently the only way we provide the menus. Access from DB or COOL has not yet been tested, as we don't use this yet in athena. A complete test will be implemented once we have all configuration methods available.

This concludes ATR-20884