[ios] Resources folder is excluded in the project.yml

[Paulescu]

Hi there,

I managed to run the LeapSloganExample for iOS on my end, however, I encountered 2 issues that should be fixed/improved:

1. The resources folder is currently excluded in the project.yml file, which means that when you bootstrap the project with xcodegen, there is no Resources folder to put the model bundles in. I think the folder should not excluded in project.yml.

2. Nowhere in the documentation or code I could find the URL where the Liquid model bundles are. I think it would be super useful to add at least a comment in SloganStore.swift where we call the Bundle.main.url() with the link to https://leap.liquid.ai/models.

Pau