Add commands to events

[mdsimmo]

What problem does the feature solve
When something happens in Bomberman, it is difficult for server owners to notice the event, so it is hard to implement custom behavior.

Describe the solution you'd like

• Let server owners add a list of commands to run on each event.
• Should be specific to each game.
• Should use the localisation system to build the commands, thus, allowing for complex expressions

Describe alternatives you've considered
Use {#exce|...} in messages. But using #exec is rather insecure and should be disabled.