Adapt the documentation for error handling for services regarding Quarkus

[GuentherJulian]

The guides dealing with handling exceptions need to be adapted regarding Quarkus. The devon4j-rest module provides the RestServiceExceptionFacade for handling exceptions throughout services. There are some guides that mention this approach:

• Exception guide
• REST guide

However, we cannot use this for Quarkus. For our reference project we have implemented our own solution which also uses the javax.ws.rs.ext.ExceptionMapper (devonfw-sample/devon4quarkus-reference#24).

The guides should describe a general way to handle exceptions using ExceptionMapper. Then we can link a separate guide for Spring applications using the RestServiceExceptionFacade from the devon4j-rest module.

Links for handling exceptions in the Quarkus documentation:
https://quarkus.io/guides/resteasy-reactive#exception-mapping
https://quarkus.io/specs/jaxrs/2.1/index.html#exceptionmapper