Problem description
There are a lot of questions and issues on Error Response format and content.
Currently the documentation lists the different error codes and cluster them into separate tables, depending on their nature: i) syntax exceptions, ii) service exceptions, and iii) server errors.
The tables do not contain HTTP status values which may introduce ambiguity. There are also differences between the list and the examples in CAMARA_common.yaml

There are also questions on the Error Response format returned by OpenId Connect flows.

Expected action
Update Chapter 6 to provide clear requirements on Error Response content.
Decide what should be changed and aligned in CAMARA_common.yaml.

Indicate when other standard formats can be used.

Additional context
Resolution of Issue #127 can be extension/exemplification of Chapter 6 requirements.