License / terms for models in model collections

[dsheldon]

We should:

1. Add a license and/or terms of use for models in our public-facing model collections. We should check with the S&T team about what license we can use. If there are no restrictions I would suggest CC-BY.
2. Make sure the collection index includes attributions and disclaimers as described in S&T terms of use: https://science.ebird.org/en/status-and-trends/products-access-terms-of-use. (I know we link to S&T prominently already, I'm suggesting adding their exact text for citation and disclaimers.)

[ethanplunkett]

The code for building collections now adds a license and the eBird's exact attributions and disclaimers. The Avian Influenza collection reflects those changes. The default collection has not been updated, but will be when we next update the models (I think soon).

Only pending task:

• Rebuild default collection.