different systems often have a different concept about what a user is.
some systems use a simple username, some use a structured user name.
bugzilla uses a login name structured as an email address. The login name
serves both to identify the user and as a contact address for the user.
The user@domain structure in names helps bugzilla span virtual org
boundaries, an environment it's typically deployed in.
bugzilla uses a login type of DB or LDAP to determin the correct
behavior. seems i should introduce a new authn method, maybe EXTERNAL, to
tell it how to behave with remote user. will need to also define a default
email domain, concept so that the user account can have an email address
without further lookup. seems that bugzilla does all internal authz
checking against an account with an email address looking structure.
