gpui-component-style theme for [egui], ported from
gpui-component.
Quick start
use egui_components_theme::Theme;
# let ctx = egui::Context::default();
Theme::dark().install(&ctx);
Components in the sibling egui-components crate read the theme
from [egui::Context::data] via [Theme::get], so installing it once at
startup (or whenever the user toggles light/dark) is all that's required.