Multi site/domain management

Although same chat code can be used across websites, there should be an explicit way to separate these inside the dashboard and eventually, in reports. This should be useful for one admin to administrate several customers accounts if they wish to do so, and then get differenciated reports from analytics and website chat/support activity tracking. This could be achieved by assigning a different tracking id to the chat code after (for instance) clicking an "add new site/domain" button within the dashboard.