Removed %jlevel% PAPI placeholder in favor of following new placeholders:

• %jlevels_level% - current level
• %jlevels_xp% - current xp
• %jlevels_required% - xp required for level up

• Added a maximum level
• Added level colours (set with colour: "<colour_code>" inside level-rewards)
• Removed feature to use different language depending on Player's locale