Enable OTP 2FA

- Update SchebTwoFactorBundle to version 3
- Enable Google 2fa on the bundle
- Disallow ability to use both email and google as 2fa
- Update Ocramius Proxy Manager to handle typed function & attributes (from PHP 7)
- use `$this->addFlash` shortcut instead of `$this->get('session')->getFlashBag()->add`
- update admin to be able to create/reset the 2fa

src/Wallabag/UserBundle/Mailer/AuthCodeMailer.php

@@ -78,7 +78,7 @@ class AuthCodeMailer implements AuthCodeMailerInterface
      *
      * @param TwoFactorInterface $user
      */
-    public function sendAuthCode(TwoFactorInterface $user)
+    public function sendAuthCode(TwoFactorInterface $user): void
     {
         $template = $this->twig->loadTemplate('WallabagUserBundle:TwoFactor:email_auth_code.html.twig');