Keep Some Inventory

This is a full rewrite of the pack but the main differences are as follows:

• You can no longer configure the pack through a scoreboard, the settings should be like the default settings before
• Updated to 1.21+ only for less code and better performance
• Experience orbs now also stay for 10 minutes instead of 5 minutes
• Items that should be dropped now include vanilla minecraft tags and modded c tags for better compatability
• Now uses an advancement to detect death instead of a scoreboard, making it fully compatible with the doImmediateRespawn gamerule
• Uses macros to drop items and experience to improve performance