feat(content-distribution): reserved taxonomies

[miguelpeixe]

Implement the support for reserved taxonomies, starting with CAP's author taxonomy, as it requires custom handling.

This PR also changes the distribution of taxonomy terms, syncing them via name instead of slug. This allows for a more predictable behavior connecting with existing terms.

Testing

1. Double check unit tests are accurate
2. Distribute a post with categories and tags via CLI
3. Confirm the post gets distributed with the correct terms
4. If you don't have CAP active, register the author taxonomy somewhere in the plugin code:

register_taxonomy( 'author', 'post', [ 'public' => true ] );

5. Set a term to your post and distribute:

$term = wp_insert_term( 'Test Author', 'author' );
wp_set_object_terms( <post-id>, [ $term['term_id'] ], 'author' );
Newspack_Network\Content_Distribution::distribute_post( <post-id> );

6. Confirm in the node that the author taxonomy term is not distributed

[naxoc]

Looks good! 👍

[github-actions]

Hey @miguelpeixe, good job getting this PR merged! 🎉

Now, the needs-changelog label has been added to it.

Please check if this PR needs to be included in the "Upcoming Changes" and "Release Notes" doc. If it doesn't, simply remove the label.

If it does, please add an entry to our shared document, with screenshots and testing instructions if applicable, then remove the label.

Thank you! ❤️

[matticbot]

🎉 This PR is included in version 2.4.0-alpha.1 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀

[matticbot]

🎉 This PR is included in version 2.4.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀