Use iw_default_author for the h-card

[asuh]

Right now, the representative .h-card component is using get_the_author_meta() to grab the default author data to apply it to the card. There's no logic to distinguish for post authors and representative h-card authors.

Here's an example: https://github.com/dshanske/iw26/blob/trunk/template-parts/biography.php

The Indieweb plugin offers iw_default_author data and it would make more sense to use this for the default for the repreentative h-card, especially when there could be more than one author.

Luckily, Indieweb plugin states that it'll always default to a specific user who has made a post, as long as no other users or profiles have made posts.

Once this work is completed, I need to test this is compatible with the IndieBlocks plugin for Gutenberg support.

[asuh]

I think the logic is updated to support most of this.

98386d5