Added Spring's Nullable Annotation to CAE Handlers

The update to spring 5.3 included a change how spring webmvc treated conversion of path and request parameters whose values are null. Hence we refined most of our CAE handlers to accept null values and to respond with NOT_FOUND (404) in this case instead of producing a conversion error.

(CMS-22329)

Corrected Sitemap Generation Ports

There was some confusion throughout the application properties files and the documentation, concerning the port of the sitemap generation endpoint. The endpoint is still included in the spring boot management context of the Live CAE and is available by default at port 8081 in the Docker Container and mapped to port 42181 of the host. The obsolete property cae.sitemap.cae-port has been removed.

(CMS-22102)

Allow Customize.Mode.APPEND for permittedLinkParameterNames Handlers

It is now possible to add entries to the permittedLinkParameterNames of handlers via customizer.

(CMS-21890)