👩‍🎓 Consume affiliation/collaboration values as objects with 'name'

[fwkoch]

This PR updates the template to work with improved affiliations in MyST frontmatter added here: jupyter-book/mystmd#535

With this change, affiliations are now objects with name, address, etc. that are able to be referenced by id. Notably, they also have collaboration boolean (so collaborations are simply affiliations with this flag set to true).

In the template, I just changed affiliation.value/collaboration.value to affiliation.value.name/collaboration.value.name. In the example myst.yml file, I moved the affiliations to separate objects, setting the collaboration flag where necessary.

A couple notes:

• Affiliations will still work when defined as simple strings, as found in the page frontmatter here: https://github.com/dressedfez/myst_template_physical_review_journals/blob/main/examples/paper.md. Since there are no collaborations or anything there, I just left that file as-is.
• There may be more updates you would like to make to this template to support the other affiliation data; for now, this just maintains existing functionality.

Let me know if you have any questions or concerns!

[rowanc1]

Thanks for the quick merge @dressedfez! Updates are live in mystmd v1.1.10!

🚀