Added the Add User Name page

Added the AddUserName page, which will be used to promote a given user
to a driver by specifying a username.
Also edited the user object to find be able to find out if the user is
driver or not. Enabled the function through the monlift object
interface
Added the addUsername process

User can now have a formulaire to add a username when he is  not yet
driver and he want to add a lift
add Car Form and the part of the process to create car

Also updated the way user and token are stored.
edited typo in monlift.js
merge addLiftFlow