Furomon

- Add support for logos in the sidebar.
- Fix path used for search page.
- Tweak height for short pages on mobile (100vh resulted in a scroll).
- Tweak definition lists.
- Tweak line height in contents, to accommodate for code literals.
- Use `em` as the unit for layout sizes.
- Start writing theme's documentation.
- Deploy documentation on <https://pradyunsg.me/furo/>.

Initial release.

{important}
This release was not correctly versioned and is not installed preferentially over beta4.


- Add CSS variables for header foreground and background.
- Add styling for captions.
- Add styling for correctly handling permalinks.
- Correctly stylize _only_ definition lists with the rules intended for them.
- Fix next/prev links flowing into one-another by limiting width to 50%.
- Fix positioning of collapsed contents sidebar icon.
- Fix shrinking arrows in next/prev links.
- Include `basic` theme's JS files unconditionally. This should help with compatibility with various Sphinx extensions and Read the Docs.
- Make `math` elements scrollable, when wider than the page.
- Tweak images to be responsive.
- Tweak spacing of paragraphs.
- Tweak location of Read the Docs' injected version helper.