Authentication should be removable for (non-editable) deployed public catalogue

[DILewis]

Currently all pages go through eXist authentication. This is very useful for the MerMEId editor.
Most deployments of published catalogues are likely to be open access, so it would be good if you could either:

• control the authentication to exclude pages or forms of access from access control; or
• provide an alternative deployment dockerfile that has no authentication, but is also effectively read only
  (I think the relevant config is currently handled in MerMEId/jetty-exist-additional-config/etc/webapp/WEB-INF/web.xml )

[peterstadler]

The behavior has changed since #87, so unauthorized access is granted to viewing HTML and XML, see e.g. https://mermeid.edirom.de/modules/present.xq?doc=nielsen_maskarade.xml

Is that already enough to resolve this issue?