Add http_response_headers in http_handlers of any kind

Why it matters

This feature enables users to specify custom HTTP response headers for any type of http_handlers. It enhances HTTP responses by allowing more control over headers, which can be useful for security, caching, or other HTTP protocol customizations.

How to use it

Users can add the http_response_headers configuration to their http_handlers settings in the ClickHouse server configuration to specify desired HTTP headers to be included in responses.