Redocly: Add support for content on redocly pages

[nginx-jack]

I know. I can't help myself. More redocly changes.

This removes the concept of a redocly "layout" in hugo, and instead, uses it as a standard partial in our default single.html .
The main benefit of this is that you can have other content on a page besides redocly.

The frontmatter you need:

tags:
  - api
doctypes:
  - reference
nd-api-reference: "./api/example.json"

This stops the redocly js files loading on every page.

This implementation essentially uses a css breakout, to make it spread beyond the grid.
It's still using the data-grid attribute.

Examples across all three types of media queries.

[github-actions]

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[lamATnginx]

Do we want tiny redocly width?

[nginx-jack]

Do we want tiny redocly width?

Let me see if there's an easy way to expand it beyond our max content grid size 🤔

[danielledeleo]

Redocly really needs to be full width. It's really unusable and looks awful when it's letterboxed inside our docs.

[danielledeleo]

[danielledeleo]

The Redocly search field is hidden by the floating navbar when scolling.

[danielledeleo]

Remove side padding, add gray borders top and bottom.

Scrolling hides the Redocly sidebar behind the navbar.