* Encode URL set to rd parameter.
URL encoding that parameter solves PR #476.
Some URL parameters set during redirection were magically disappearing
after the redirection due to the authentication process. By using URL encoding,
those parameters should not be stripped anymore.
* Fix integration tests.
Providing a GA tracking ID allows administrators to analyze
how the portal is used by their users in large environments,
i.e., with many users.
This will make even more sense when we have users and admins
management interfaces.
When a user use Authelia for the first time no device is enrolled in DB.
Now we test that the user does see the "not registered" message when
no device is enrolled and see the standard 2FA method when a device is
already enrolled.
A message is now displayed to the user when he first sign in
in Authelia letting him know that a device must be enrolled.
Also introduce a message letting him know when he is already
authenticated.
