The user authentication was currently done using a cookie and following
the same style of token as the HTTP Basic authentication (i.e. a
concatenation of user and password joined with a ':' encoded with
base64).

This authentication has been replaced by a standard HTTP Basic
authentication.

Red background was added to the body of the login view for debugging
purposes, but shouldn't have passed to a stable release. This commit
removes the red background configuration.

The application appearance has been improved applying Bootstrap formats.