[Feature] Prestige Classes

For long-term re-playability, add "prestige classes" which can only be unlocked after a long time of playing and which go along with the play style of the base class.

For instance, after leveling up a warrior fully for several months, you could choose to remain a warrior, or you could choose to "prestige" into your choice of three classes: knight, samurai, or barbarian. But when you do this, you have all your gear, abilities, etc. reset.

When people see a knight or barbarian, they immediately know you have put your time in playing in order to unlock that prestige class.