[Refactoring]: Avoid deleting .class files every build

[kwvanderlinde]

Describe the problem

During development, if I try to run a second MapTool instance via Gradle while another is already running, the first is likely to start generating java.lang.NoClassDefFoundError during the build due to certain GUI .class files having been removed.

The improvement you'd like to see

I would like the instrumented and uninstrumented versions of each .class file to be kept separate, and the defensive deleting of .class files to be removed.

Expected Benefits

The developer experience will be improved in two ways:

1. We will be able to run multiple MT instances without the builds interfering with each other.
2. Builds will be faster as the compileJava task will not be constantly out of date.

Also there won't be a need to maintain a hardcoded list of .class files to delete in order to avoid duplicate $$$getFont$$$ methods.

Additional Context

No response