Add Swap component for toggle functionality

src/components/Swap.js

@@ -0,0 +1,13 @@
+import { $html } from "sigpro";
+import { joinClass } from "../core/utils.js";
+
+/** SWAP */
+export const Swap = (props) =>
+  $html("label", { class: joinClass("swap", props.class) }, [
+    $html("input", {
+      type: "checkbox",
+      checked: props.value
+    }),
+    $html("div", { class: "swap-on" }, props.on),
+    $html("div", { class: "swap-off" }, props.off),
+  ]);