Allow 3rd-party extensions to contribute in-memory launch config

Currently, vscode-java-debug searches the .vscode/launch.json file for a launch config matching the classname+project name.

https://github.com/microsoft/vscode-java-debug/blob/415ae57296c10e9ffd2204ab66e22cb9d929259c/src/extension.ts#L450-L459

If none is found, a default config is built in memory:

https://github.com/microsoft/vscode-java-debug/blob/415ae57296c10e9ffd2204ab66e22cb9d929259c/src/extension.ts#L427-L433

I'd like the JBang extension to provide a custom in-memory config, where we can dynamically set the add-opens args for instance, to be able to keep in synch' with the JBang directives in the java file, rather than having to create/update .vscode/launch.json at some point.

Would be nice if vscode-java-debug allowed 3rd-party extension to contribue launch config participants, that, if they match, would then provide a custom in-memory config, if none was found on disk.

See the video at the 4'37" mark and https://twitter.com/fbricon/status/1698735665259626996 for context

cc @maxandersen

从 src/extension.ts 第427-433行和450-459行中的 launch-config 查找和回退构造开始。跟踪默认内存中配置的选择方式，然后确定像 JBang 这样的第三方参与者如何提供匹配的配置。当磁盘上不存在匹配项时，扩展能够提供自定义的内存中配置（包括动态派生的 add-opens 参数），即视为完成。