Dark Mode Support

[g30r93g]

Please implement dark mode support for Swift Package Registry.
Love the registry, I think its a great idea. :)

[twodayslate]

Bootstrap is currently used for theming. Currently, it looks like dark mode is not supported. twbs/bootstrap#27514

tailwind looks like a decent alternative

[twodayslate]

Bootstrap 5 has officially been released but still does not support dark mode.

[silvinor]

This may help - vinorodrigues/bootstrap-dark-5