remember previous authentication choice

Summary

When authentication choice is selected, propose a checkbox for remembering last successfull authentication choice, and playing it automatically on next attempts to log in.

Design proposition

• set a dedicated cookie to store the last authentication choice
• only set the cookie if the authentication is successful
• forget the cookie when the checkbox is uncheck and the authentication succeeds
• only plays authentication choice when login form is displayed first, not when there are errors
• allow a timer for the user to see the automatic redirection, and stop it if necessary