Update payload.config.ts to work with Payload v2.
Update README.md with info on payload package.
Remove yarn.lock files for now, since updating the package versions made the lock files out of date.

Fix favicon URL by including the base path.

We only need packages/astro for the site.
Update the compose files to not try to launch astro in the container.
Add error handling to posts.astro.

Add Post.astro component to render the Payload post.
Add a Payload link to the header.