* Add a private static list of `Character`, `allCharacters`, which will contain all our characters. In the constructor, you need to add every new `Character` to this list.
* Add a static method, `printStatus`, which takes no parameters and returns a formatted String that lists `allCharaters`. The awaited format is as follows with new line at the end :
Finally, add a static method, `fight`, which takes two `Character` objects and returns the winner in the fight.
During the fight, the first one attacks, then the second one, then the first, then the second and so on until one of them reaches 0 in its currentHealth. When `currentHealth` for one of them reaches 0, the other one is the winner.