Two-factor and Oauth authentication

[xtremespb]

We need to create the two-factor (Google Authenticator-based, I think) and Oauth authentication services.

• Oauth: currently Zoia supports the "straight" authentication method (username and password), but it requires to verify user's E-mail address. It's necessary to simplify that process.
• Two-factor auth: due to security reasons that may be a really nice idea which is relatively easy to implement