Live Session - Running sessions in parallel

As a lecturer, I would like to be able to have multiple running sessions in parallel, such that I can coordinate multiple classes more easily. Acceptance criteria - It is possible to start a session even though another session is already running. - When multiple sessions are running under the same account id, participants can choose which session they want to participate in. - All running sessions are listed in the corresponding area of the session overview. - The running session screen is accessible for all sessions that are running. The session to subscribe to is decided based on the session id in the URL. - A dropdown with links to all running sessions is presented in the navbar (instead of a single button).