Add Folia support.

[shishioko]

[16:49:17 ERROR]: [DirectoryProviderSource] Error loading plugin: Could not load plugin 'CartLoader v2.0.0' as it is not marked as supporting Folia!
java.lang.RuntimeException: Could not load plugin 'CartLoader v2.0.0' as it is not marked as supporting Folia!
        at io.papermc.paper.plugin.provider.type.spigot.SpigotPluginProviderFactory.build(SpigotPluginProviderFactory.java:40) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.plugin.provider.type.spigot.SpigotPluginProviderFactory.build(SpigotPluginProviderFactory.java:28) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.plugin.provider.type.PluginFileType.register(PluginFileType.java:72) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.plugin.provider.source.FileProviderSource.registerProviders(FileProviderSource.java:95) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.plugin.provider.source.DirectoryProviderSource.registerProviders(DirectoryProviderSource.java:52) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.plugin.provider.source.DirectoryProviderSource.registerProviders(DirectoryProviderSource.java:17) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.plugin.util.EntrypointUtil.registerProvidersFromSource(EntrypointUtil.java:15) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.plugin.PluginInitializerManager.load(PluginInitializerManager.java:113) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at net.minecraft.server.Main.main(Main.java:112) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paper.PaperBootstrap.boot(PaperBootstrap.java:21) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at org.bukkit.craftbukkit.Main.main(Main.java:242) ~[folia-1.21.8.jar:1.21.8-5-7a1c5c7]
        at io.papermc.paperclip.Paperclip.lambda$main$0(Paperclip.java:42) ~[app:?]
        at java.base/java.lang.Thread.run(Thread.java:1570) ~[?:?]

[YourMJK]

I haven't looked into it much yet, but adding Folia support for this plugin is probably not a small task due to the regionized worlds and different schedulers.

Maybe I'll work on this but I can't promise anything and if I do give it a shot, it won't be in the next few weeks.

Until then, I'm open to PRs from people with more experience than me with Folia (which is zero).