MosaicCore 0.0.9-alpha for Minecraft 1.20-1.20.1

• Fixed cancel-ability of events
• Thread safety
• Listen function is infixed on PluginContainer
• New subscriber function
• Fixed priority
• Moved plugin containers into implementations

Full Changelog: https://github.com/MosaicMC/MosaicCore/compare/a0.0,8...a0.0.9