User selection

[erikvullings]

Create a dropdown at the top right to select the user from the list of users.

ATM I don't want to use authN, since it is a safe environment (albeit we may specify a generic username/pwd to protect all services, including admin tool, etc.,).

The selected user determines whether you have the right to:

• check items
• resend or confirm messages
• start/pause/stop time
• create/stop sessions

One use case is that multiple people would like to monitor the timeline, but you don't want them to mess around with it.