quasar should set css color-scheme property

[rotu]

For dark mode globally and on individual components, quasar should set the css color-scheme property
https://developer.mozilla.org/en-US/docs/Web/CSS/color-scheme

This would allow using the helpful CSS light-dark() function to set brand colors, e.g. in quasar.variables.scss: $negative: light-dark(red, maroon).