docs: Add base readme

Author: Ehesp

README.md

@@ -0,0 +1,23 @@
+# FirebaseUI for Web
+
+This repository contains the source code for the FirebaseUI for Web project rewrite, focused on providing Authentication components for popular JavaScript frameworks.
+
+## Installation
+
+To get started, install the React or Angular package:
+
+<details>
+  <summary>React</summary>
+
+  ```bash
+  npm install @firebase-ui/react
+  ```
+</details>
+
+<details>
+  <summary>Angular</summary>
+
+  ```bash
+  npm install @firebase-ui/angular
+  ```
+</details>