[ALOY-84] Models are only generated in the index component

Model generation still makes the assumption that alloy files consist only of an app.js. Therefore, models are only generated into the index component object. There's a few things that can be remedied here. * Models should not be dumped as variables into component objects. They should be generated into their own commonjs modules. Those modules will be housed in Resources/alloy/models at runtime. * It would be nice if the models were accessible from the Alloy namespace. Perhaps as Alloy.Models.MODEL_NAME * Models will be made accessible, as needed, from all component objects via require() or the Alloy namespace. * Models will than be able to make changes in multiple parts of the application, not just the current component object.