Step #1 is to package cockpit-machines. I haven't dared to touch JS with even a 10ft pole, so I can't help you with that but I can highly recommend to take a look at how similar packages work and copy what they do.
Modules come later; they just wire up some packaged applications to the system. I'm not familiar with the project but it seems like cockpit-machines is a UI of sorts? If it doesn't need any system configuration, you don't need a module. Users would just install the package, run the binary and that's that.
Modules are for when you need e.g. a system service like a web server.