Desktop: Add taskbar icon on Windows (#3225)

* include icon as resource on windows

* load icon

desktop/build.rs

@@ -0,0 +1,8 @@
+fn main() {
+	#[cfg(target_os = "windows")]
+	{
+		let mut res = winres::WindowsResource::new();
+		res.set_icon("assets/graphite-icon-color.ico");
+		res.compile().expect("Failed to compile Windows resources");
+	}
+}