Portal landing page

Entering on mCube portal, a guest landing page is showed to no-logged users. Notice that if users are already logged they will be redirected on the relative user-role page.
The page presents a descriptive portal header, a login button and a button for the access the workspaces.
From the landing page users can:
- Sign in
- Access user's workspaces
Sign in
By clicking on the login button users can perform authentication.

Once the successful authentication users will be redirected to user page.
