Add items-based economy feature

• Implemented core functionality for items-based economy.
• Updated gradle-wrapper.properties to use Gradle 8.1.1.
• Added configuration loading and saving in PwingEco.java.
• Added a new ReloadCommand class to handle the reload command.
• Updated plugin.yml to include the new pwingeco command and its permission.
• Improved command registration in PwingEco.java.
• Adds Next Tier conversion and whatnot
• Skript 2.10.0 support update as well

Take/remove money
take %number% [of] [pwingeco] %string% from %player%
remove %number% [of] [pwingeco] %string% from %player%'s balance

Check if player has money
[pwingeco] %player% has [at least] %number% [of] [pwingeco] %string%

Expanded skript expressions see wiki