Make sure the CMS is still accessible if the hst:platform config is broken or doesn't have a matching host

Currently, every cms request goes via the hst filter in hst platform.

The cms host is matched below the hst:intranet configuration.

However if there cannot be matched a host, the HST platform returns an error page.

This means that if in /cms/console you mess up the hst configuration, the entire cms and console cannot be accessed any more.

The HstFilter / hst platform however should behave differently: Instead of returning an error in case no host can be matched, we can perhaps better delegate to the next servlet filter in case no host can be matched since then at least the cms and console stay accessible