Pages were missing from the sitemap after the reorganization. Added them
back in.
Also added an optional priority that can be specified by including
`sitemapPriority` in content metadata. Used on the deprecated Auth
Helpers pages to see if we can tweak the relative SEO ranking for them.
Begin the process of moving our MDX files into their own content directory.
Fixed a few minor bugs re: ToC and tabs not rerendering consistently on page navigation. (The ToC thing wasn't a problem before the refactor, the tabs thing is a problem on prod.)
Moved MDX files can't import their own components, so everything they require needs to be back in the component prop for mdx-remote's serializer. Cleaned this up a bit and lazy-loaded heavy/rare stuff. Also, the component prop doesn't take arbitrary objects (only actual components), so imported data has to be wrapped in a component.
Joel Lee