docs: migrate documentation to Fumadocs

apps/docs/next.config.mjs

@@ -0,0 +1,16 @@
+import { createMDX } from "fumadocs-mdx/next";
+
+const withMDX = createMDX();
+
+/** @type {import("next").NextConfig} */
+const config = {
+  output: "export",
+  reactStrictMode: true,
+  trailingSlash: true,
+  images: {
+    unoptimized: true,
+  },
+  transpilePackages: ["@homarr/custom-widgets", "@homarr/definitions", "@homarr/workshop"],
+};
+
+export default withMDX(config);