Added
- Added a system for saving the player's inventory when entering a fight.
- The player's inventory is automatically restored after the fight ends.
- Added new PlaceholderAPI placeholders for the Gladiators mode:
%spacepvp_gladiators_last_winner_prefix%
%spacepvp_gladiators_last_winner_name%
%spacepvp_gladiators_last_winner_displayname%
%spacepvp_gladiators_wins%