Multiple Themes: Transition Headstart Content to Pattern + Move to template

[pbking]

As a part of the work to make theme defaults more consistent (pNEWy-fG8-p2), we'd like to remove a lot of the configuration done by headstart.

In going through this process, we found home page designs for many themes that are only provided via Headstart annotations. Calvin, for example:

By default, the theme is configured by headstart to generate this content in a page assigned to a custom template — header-footer-only or footer-only template — and the site's reading settings adjusted to display this page. If we were to remove this configuration from headstart, the theme would not match the expectation of the demo site with no way to provide this design to the user.

So, to remove headstart configurations while still achieving the design intent of the theme, there are a couple options:

1. Add the content to a default template (such as index.html or home.html), via a pattern or directly to the template. This could break existing sites by overriding their existing template structure.
2. Alternatively, create a new theme (such as Calvin-2) with the templates configured as desired, retire the previous version.

The following themes are affected by this situation:

• [ ] Calvin
• [ ] Ames
• [ ] Farrow
• [ ] Hari
• [ ] Heiwa
• [ ] Dorna
• [ ] Appleton
• [ ] Meraki
• [ ] Antonia
• [ ] Appleton
• [ ] Quadrat

cc @ianstewart

[mikachan]

I think Quadrat can be added to this list too.