LightDark and DarkLight buttons

[AucT]

Hello! This v5.3 version is awesome. We waited 5 years for dark mode and at last we got it!
Congratulations to all who made and all of us who waited.

Ok, I want also to thank for nice new bg utilitity classes.
And I think it will be awesome if we had some buttons that will change color depending on theme.

In particular, I mean we want bootstrap to have
btn-light-dark (light in light theme and dark in dark theme)
btn-dark-light (dark in light and light in dark).

mic drop! 🎤