Move the logout inside the main header bar

[tloubrieu-jpl]

💡 Description

Currently the logout button is on top of the header bar, see screenshot:

It would look nicer inside the main header bar, on the right side, near FAQ.

'logout' would be enough, I don't think we need the username to show here. or maybe in a tooltip...

[jordanpadams]

@tloubrieu-jpl is this something we really need? or is it a nice-to-have feature?