This commit merge the two website menu items in order to ease user flow
inside Odoo. When clicking on the Website item a server action is called
that decides to redirect the user either to the dashboard if the user is
an admin or a website publisher, either to the website for other people.
Overriding this method allows to define a specific behavior. Future commit
will also redirect sales people to the website dashboard.
Dashboard itself is customized to add a header used to display a website
button. It will be used in future commits to add other new stuff to the
dashboard.