perf(v2): smaller bundlesize by embedding metadata to content (#2088)

* wip embed metadata to content

* embed metadata in blog as well

* refactor

* update test

* yarn lock

* avoid overwriting file everytime we run new nodejs process

* nits

packages/docusaurus-utils/src/index.ts

@@ -252,3 +252,13 @@ export function normalizeUrl(rawUrls: string[]): string {
 
   return str;
 }
+
+/**
+ * Alias filepath relative to site directory, very useful so that we don't expose user's site structure.
+ * Example: some/path/to/website/docs/foo.md -> @site/docs/foo.md
+ */
+export function aliasedSitePath(filePath: string, siteDir: string) {
+  const relativePath = path.relative(siteDir, filePath);
+  // Cannot use path.join() as it resolves '../' and removes the '@site'. Let webpack loader resolve it.
+  return `@site/${relativePath}`;
+}