DemoBox

• Added option for per-player setup function (#4 by @DrexHD)

• Updated to 1.21.8 for ModFest: Toybox
• Added /demobox sign command for convenient creation of portals

• Fixed an issue where player data could be lost upon dying in a demo

Updated to 1.21.1

Updated to 1.20.4

• Add welcome message
• Add predicate api support

Fix structures generating

Initial version