Set dynamic response headers for all REST resources including Multi in a generic way

[dastrobu]

Description

I'd like to set custom response headers on all resources in a generic way.

The naive approach would be to implement a @ServerResponseFilter.
However, as pointed out in #44898 (comment), this approach does not work for resources returning a Multi.

Having a generic way to set custom response headers is a prerequisite to supporting features like setting a traceresponse header (see 11931 for an example use case).

Currently, one would need to implement a @ServerResponseFilter handling all non-multi resources and set the response headers on each multi resource individually with RestMulti.fromMultiData(...).headers. There is also #44902 preventing even this approach for SSE-annotated resources.

I'd propose reconsidering adding support for @ServerResponseFilter on Multi resources or thinking about an alternative way to set response headers in a generic, filter-like way.

Implementation ideas

No response

[quarkus-bot]

/cc @FroMage (rest), @stuartwdouglas (rest)

[geoand]

I am all for coming up with something better than the current state, but I am -1 on using @ServerResponseHandler for this