participant home screen - html template (room)

Create a html template for the room the participant can join (detail view of a room for participants).

This is a child of #14 (closed)

Proposed changes

• Added participant-room component
• Show (and link to currently existing) functions which a participant has in room-view instead of room-detail:
• This is the new 'Create comment'-button @hdrs71
• Changed navigation when joining a room

For testing

• Login as participant and join a room - you should see now the functions which a participant has in room-view