Refactor site into layouts

[camchenry]

What this PR does

This PR adds some base/main layouts to the website, so that all pages can share common HTML, CSS, JS, etc.

Why I chose this approach

Breaking the site into layouts/components will make the site easier to maintain because content can be added independent of needing to keep the layout HTML/CSS updated. We can also update the CSS/JS for the whole website more easily.

This PR does not address any of the usability/accessibility issues in the site, or formatting issues. Those can be handled in a future PR.

[hildjj]

Can we use 11ty version 2, even though it's not released quite yet? I'd rather not have to relearn stuff when they ship.

[hildjj]

It used to be that we could load the site from file: URLs. With the absolute paths that we've changed to, that no longer works in the _site directory. This isn't a big deal now that we're mostly going to be running from browser-sync, I suppose. Just interested in discussing.

[hildjj]

The rest of this looks fine. I'm interested in response to my two other comments, though, before I merge.

[camchenry]

Can we use 11ty version 2, even though it's not released quite yet? I'd rather not have to relearn stuff when they ship.

I didn't realize there was a version 2 coming up. I'll look into, but given the framework position on backwards compatibility, I'm guessing it won't change much for us.

[camchenry]

It used to be that we could load the site from file: URLs. With the absolute paths that we've changed to, that no longer works in the _site directory. This isn't a big deal now that we're mostly going to be running from browser-sync, I suppose. Just interested in discussing.

If it's important, it's probably possible to get this working again. On the other hand, I think running a dev server is almost a necessity these days. Still, that's not an eleventy thing, I just made it absolute to make it easier to develop.

[hildjj]

given the framework position on backwards compatibility, I'm guessing it won't change much for us.

It changes the config file at least with respect to how to configure browser-sync. I can make it work either way, but if we switch to v2 now, I won't have to re-figure that out when we upgrade.

[camchenry]

I will get around to updating this, just had some things come up, so I may not get to it until next week.

[camchenry]

@hildjj I updated the dev server config. It looks like it pulls in fewer dependencies now and is built-in to the framework. Otherwise, npm run start seems to work basically the same.