plugin-spi 0.4.0

This is a breaking release of plugin-spi to support SpongeVanilla 12 and its ModLauncher 10 environment. This come with a few QOL improvements too.

• Require Java 21 or more.
• Update plugin-meta to 0.8.2.
• JVMPluginResource is now an interface and is implemented by the platform.
• ClasspathPluginResourceLocatorService is now based on the system property rather than the system classloader and will load only jars, no directories.
• Added EnvironmentPluginResourceLocatorService to load plugins from an environment variable.
• Remove most generics in services and candidates. Most of the time they were useless and causing unsafe casts resulting in some services receiving wrongly typed arguments.
• Blackboard now has a proper setter.
• JVMPluginContainer has been replaced by StandardPluginContainer. A more general alternative.
• Same goes for JVMPluginLanguageService and StandardPluginLanguageService.
• ResourceQueryable now takes String parameters instead of URLs making it easier to use.