[REQUEST] Add appropriate metadata markup to layouts

[juliaferraioli]

Right now, I've added some (likely inelegant) markup to the default layout. However, that doesn't capture all that we could, and stories need additional markup.

Describe the solution you'd like
It would be excellent to have podcast episode metadata for each story. This may require adding new frontmatter to the stories archetype.

Additional context
I have found the JSON-LD Playground to be helpful if you're getting started with schema.org markup and JSON-LD (actually, even if you're not just getting started).

If you would like to try taking on this issue, but want some hands-on guidance, please let me know in the comments!