This commit adds the `FirebaseAuthView` class, a Flutter widget that serves as the UI for user authentication using Google and GitHub. The class uses the `AuthService` to handle the actual sign-in logic.
Features:
- Added an OutlinedButton for Google Sign-In, styled with Google's colors and logo.
- Added an OutlinedButton for GitHub Sign-In, styled with GitHub's colors and logo.
- Integrated the `AuthService` methods for Google and GitHub sign-in.
