Adding handled query parameters to list endpoints

Current situation

The 'list' endpoints now support selectors and possibly other query parameters. But there is no way for a client to know if the endpoint has handled them.

This can cause problems when tools are interacting with old orchestrator instances: they may require a filter but the result is not filtered.

Desired outcome

Add a X-Processed-Query which is a comma-separated list of processed parameters in endpoint responses.