improved error handling of service client

[hohwille]

The service client shoud report errors comming from spring boot rather than our own RestServiceExceptionFacade properly and report HTTP status code and error properly via exception.

This is an example JSON response I get from spring-boot app for undefined URL path:

{
  "timestamp":"2021-02-19T15:48:03.492+00:00",
  "status":404,
  "error":"Not Found",
  "message":"","path":"/app/services-404/rest/my-example/v1/business-error"
}