feat(docs): setup Gridsome for the website

docs/src/main.js

@@ -0,0 +1,12 @@
+// This is the main.js file. Import global CSS and scripts here.
+// The Client API can be used here. Learn more: gridsome.org/docs/client-api
+import 'prism-themes/themes/prism-lucario.min.css'
+
+import DefaultLayout from '~/layouts/Default.vue'
+import MarkdownLayout from '~/layouts/Markdown.vue'
+
+export default function (Vue, { router, head, isClient }) {
+  // Set default layout as a global component
+  Vue.component('LayoutDefault', DefaultLayout)
+  Vue.component('LayoutMarkdown', MarkdownLayout)
+}