ℹ️ WordPress/twentytwentytwo#213

This PR tries out some alternate color + font combinations for Twenty Twenty-Two, as mocked up in the theme's announcement post. These were originally intended to be a set of alternate color palettes and/or theme.json files, but I'm building them as child themes for the moment since Gutenberg does not include support for those features yet.

I don't expect that these will end up being child themes in the long term, but it works well for testing today.

A few implementation notes:

• I ran into an issue with Twenty Twenty-Two's default header image, and opened a PR to address it. You'll probably run into this issue while you test.
• Font implementation is still up in the air. Ideally these would be fully defined in theme.json, but that's not possible yet. For now I took a hacky shortcut because it was easy and could plug into an existing Twenty Twenty-Two function. If for some reason these continue to be child themes, we should bundle the actual font files instead of referencing Google fonts.
• Some themes include a slightly modified header-large-dark.html template part. These are identical to the original except they have different text and background colors assigned (for example, primary instead of foreground). This is to make the color changes a bit more noticeable on the homepage. It would be totally ok to lose this if we switch to a non-child-theme approach.
• A few of these themes use fewer colors than are actually present in Twenty Twenty-Two. This is totally fine, except I had to declare these colors twice in order to ensure existing patterns mapped to them correctly. As a result, some colors are also listed twice in the UI, which isn't great.

⚠️ Since these are child themes, you must separately install Twenty Twenty-Two in order to test them.