refactor: move Vuepress files in dedicated directory

Signed-off-by: Lucien Cartier-Tilet <lucien@phundrak.com>

content/.vuepress/client.ts

@@ -0,0 +1,13 @@
+import { defineClientConfig } from '@vuepress/client';
+import PreviewImage from './components/PreviewImage.vue';
+import ResponsiveImage from './components/ResponsiveImage.vue';
+
+export default defineClientConfig({
+  enhance({ app, router, siteData }) {
+    app.component('PreviewImage', PreviewImage);
+    app.component('ResponsiveImage', ResponsiveImage);
+  },
+  setup() {},
+  layouts: {},
+  rootComponents: [],
+});