Add dark mode toggle

[chrisduerr]

As far as I can tell, wayland explorer already supports dark mode if the browser requests it. However in Firefox when enabling tracking protection it does not send this value.

It would be nice to still have a manual toggle, even if its state is not cached, just to give the option to go dark mode when looking at a protocol for extended periods of time.

This should also be useful for people that might have a light system scheme, but just prefer wayland explorer to use the dark mode (or the other way around).

[vially]

Agree that this would be useful and it's something I would like to support. However, last time I have looked into it (#4 (review)) it seemed like Tailwind does not support both media and class based dark-mode at the same time: tailwindlabs/tailwindcss#3644.

So it's either class but lose the dark mode when JavaScript is disabled, or media but lose the ability to let the user overwrite it on a per-website basis.

That being said, it may be worth taking a closer look at it in case things have changed or I may have missed something last time I looked at it.