Markdown parser plugin

[zzap]

During the AspirePress meeting, we were discussing easier ways to update the website, and the markdown parser (as used at WP.org) came to mind. This parser is a WordPress plugin, and it takes a file from the repository manifest.json (example) to generate pages/posts/CPTs in WordPress by using markdown files in the repository. We still don't know if the parser is open-sourced and what the code looks like.

This way, the content can be updated simply by merging to main branch, while anyone can contribute to it.

[toderash]

Context: this will publish from a folder in a gh repo to the CPT & taxonomies created in #91 and should be run every 12-24 hours via wp-cron.

[afragen]

https://github.com/erusev/parsedown has been updated to v1.8 which is now PHP 8.4 compliant. I haven't tested in PHP 8.5.

It's a nice, fast parser.