After fixing bug #915 we can define domains by any suffix like .co.uk or .dk by
inputting a list in settings.
However a much better solution would be to make the definition of domains
pluggable so any definition is possible. The plugin would encompass the two
methods from Domain: isValidDomainName and domainNameFromHostname
A better implementation of the plugin than the current is to use the list from
NOTE: This bug is originally from Bugzilla bug_id=1072.
This bug was previously assigned to Unassigned.