Vadmin v1.0 installer: Cross-admin authentication method
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Cross-admins are administrators who can administer more than
just one domain, but several. Vadmin can authenticate them
using two separate ways.

SYSTEM auth method requires cross-admins to provide a valid
system password for each domain they select to administer. The
advantages of this method are that if the password gets stolen, only
one domain gets compromised. The disadvantages are that you have
to give out the system passwords, and it's rather inconvenient
to have to remember all of them.

USER auth method allows cross-admins to authenticate with their
mailbox password and then just use the passwords stored on the 
server. The advantage is that this is far more convenient than 
remembering all domain passwords, but if the cross-admin's password
is stolen, all domains in this admin's allowed list are compromised.


