Support other "external" resource types

[dellisd]

Right now the plugin can handle external style declarations, i.e. if a style resource is referenced in the base module's merged manifest that isn't actually included in the base module.

This isn't currently possible with other types of resources (e.g. strings or xml resources) which forces us to include some dependencies in the base module that we really shouldn't need to and inflates our base APK size.

---

The plugin is already capable of identifying resources of any type that are referenced in the merged manifest and not included in the base module, so perhaps the plugin could locate these resources from their original source and effectively copy their values into the base module (as generated resources) to satisfy the resource linking process without having to actually include a dependency on those dependencies.