add a java problem matcher to use in tasks

[maxandersen]

Would be nice if using vscode build tasks to call java/jbang directly there was a "java matcher" option like there is a bunch for node, typescript, go etc. default in vscode.

See https://code.visualstudio.com/docs/editor/tasks#_processing-task-output-with-problem-matchers

[Trass3r]

https://code.visualstudio.com/api/references/contribution-points#contributes.problemMatchers

[fbricon]

Wouldn't it make sense for the Java Debugger extension to own it?
cc @testforstephen

[testforstephen]

Adding problem matchers for build tools like Maven and Gradle has some value for the debugger, as someone may use build tool in preLaunchTask to build & launch their apps. I'm not sure what's the use case for a generic Java matcher that can be used by debugger.