feat(admin, admin-ui, medusa-js, medusa-react, medusa): Support Admin Extensions (#4761)

Co-authored-by: Rares Stefan <948623+StephixOne@users.noreply.github.com>
Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/admin-ui/src/node/webpack/webpack-aliases.ts

@@ -0,0 +1,9 @@
+import { ALIASED_PACKAGES } from "../constants"
+
+/**
+ * Ensure that the admin-ui uses the same version of these packages as the project.
+ */
+export const webpackAliases = ALIASED_PACKAGES.reduce((acc, pkg) => {
+  acc[`${pkg}$`] = require.resolve(pkg)
+  return acc
+}, {})