Modular Java builds

[sgammon]

Since GraalVM 21 (SDK release 23.1.x), the JPMS --module-path plays a larger role: support for polyglot language VMs with GVM's supported suite of languages now depends on Maven artifacts, instead of "components" distributed via the GraalVM updater.

In addition to this dependency change, VMs must be declared on the Java module path instead of the classpath, and loaded into the target app via one of the supported mechanisms (typically, module-info.java or --add-module).

Thus, it would be great to support modular Java builds, which should include:

• Use of the main_module attribute to specify the entrypoint module
• Calculation of the -modulepath flag, as applicable
• Propagate --add-opens / --add-exports flags