When editing the posts page, include relevant template settings in the Inspector

[jameskoster]

When you edit the Blog Home template a number of settings are surfaced in the Inspector:

• The blog title, maps to page_for_posts->$title
• Posts per page, maps to posts_per_page global
• Discussion settings, maps to default_comment_status global

The latter two are useful controls, and it would be good to surface them when editing the page that displays latest posts (page_for_posts), as it is a more natural flow than editing the Blog Home template. It also doesn't make sense that users are forced to navigate to the template editor to change these settings.

In this case the discussion settings replace the current control, as it serves no purpose on the page_for_posts.

When a setting is adjusted in the page edit context, the value should cascade down to the template, which itself cascades down to the options outlined above.

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Additionally we might consider hiding irrelevant data points like publish date.

[richtabor]

Noting this is blocked by #63748.