RFE: Logging in with Extra Admin user context

As a follow-on to Bug #572, would it be possible for a master admin to login as an Extra Admin, similar to the way the they can switch to a server owner account now? This would be useful in testing their access to manage the domain, as well as supporting them if they have problems.

As an added bonus, this feature could also be made available for the server owner to use with testing and support of their own Extra Admin accounts (instead of relying on the master admin to do it).

Status: 
Closed (fixed)