Release version 5.3.3

[maven-release-plugin] prepare release linkeddatahub-5.3.3

Removed unused namespaces

More XSLT fixes related to optional applications

Making application optional in XSLT writer

New HTTP test for non-existing namespaces

New HTTP test for not found files

Progress bar CSS fix

Throw 404 when file description is not found

Preserve URL fragment identifier in history pushState

`varnish_end_user_cache` volume (#279)

Fix NPE in CacheInvalidationFilter when request scope is unavailable

Fixed WebID URI logging in entrypoint

[maven-release-plugin] prepare for next development iteration

Release version 5.3.2