Refactored Dolibarr triggers

Refactored Dolibarr triggers:
Created a DolibarrTriggers abstract class.
Moved common variables out of construct class
Improved run_trigger method signature
Versions are now constants of DolibarrTriggers class.
I would have named this class just Triggers, we know we are in Dolibarr ;)
Also, I hope we'll add the Dolibarr namespace someday!