Fixed missing main-class when running a modular application.

[Xasmedy]

The RunOperation is using the java -m flag to run the modular application, but it did not provide the required main-class as of documentation -m <module>[/<mainclass>] [args...].

[Xasmedy]

Without this fix a modular application would not be able to run, and the following error would be returned: module <my-module> does not have a ModuleMainClass attribute, use -m <module>/<main-class>

ModuleMainClass is an attribute that is inserted in the module-info.class, it's useful for modular jar execution but from what I understood requires a bit more work.