Reviewer: change page URL and expose it in UI

[bzz]

Right now a reviewer page is available under http(s)://<UI-HOST>/review

It would be nice to:

• change url to /exp/<N>/review as it should be on experiment basis and
• expose it, together with /export in the menu where logout is.

[smacker]

No need to change url. I did it already and forgot about it. 🤦‍♀️