-don't strip authorization headers if the request is going to spiral / loop back to us
  -only strip if routing outside our domain 
  -moved logic from DigestAuthenticator to ResponseContext
  -moved getRealm code from DigestAuthenticator to RequestContext so that both
   DigestAuthenticator and ResponseContext can access it




git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10662 ddefafc4-47db-0310-ae44-fa13212b10f2
-fix typo in last commit (merge issue)

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10663 ddefafc4-47db-0310-ae44-fa13212b10f2