Change module configuration to be simpler

[austenmc]

Because I want to add an onRegister/onUnregister module method to be called when modules are installed/uninstalled, I want to force a module to include a class that implements the Module interface. For simplicity, this might as well handle events too, so remove the overly-flexible existing functionality allowing modules to subscribe different events to different classes, and instead direct all events to the single module class.

[Vassyli]

Having a single entry point for modules is great! We maybe should even force the class name to end with Module (and the prefix to be related to the module name).

[Vassyli]

Aside from the use statement order, looks good to me!