Iss48

Adds link_to and appropriate paths for navigating to the intro from the landing page and vice versa. Adds logic on the button at the end of the intro so if a user is present, clicking got it will navigate them to their dashboard (in the case of being directed to the intro after account creation) and, if a user is not present, navigating them back to the landing page (in the case of accessing the intro material as an unregistered visitor to the landing page).