Improve design of public event view

[mariobehling]

• Show the name of the event on the top left by default
• Change the color of the left side bar to match the color of the previous eventyay version
• Change left sidebar to be on top of the screen and add a slide in/out button like on previous eventyay version and extend the screen below the left sidebar
• Change top line "room name" white row to a light grey background