frankenstyle naming violations

[danmarsden]

The constants defined here violate the naming conventions. https://github.com/AgrosupDijon-DSI/moodle-local_ibob/blob/main/lib.php#L35-L46

please see: https://moodledev.io/general/development/policies/codingstyle/frankenstyle#constants

note this is a blocker for plugins db approval.