Add right click pop up menu

[Gabau]

Current status

• Can retrieve class to run main function -> need to select the class file with the main function (support for folder and package not provided)
• Only works in package manager
• Sets the settings and than resets it later (not ideal, best to do so programmatically, but may lead to alot of conflicts so holding off on this

TODO:

• [ ] Make it work in editor (i.e. something like running a junit test alone)
• [ ] Retrieve function to run from user input
• [ ] Programmatically set launch class and path