httptrace.TraceAndServe should set span.kind and component tags

[darccio]

Currently the net/http contrib has different wrappers that are inconsistent regarding span.kind and component tags, as ones add these tags and others don't, leading to third-parties like Orchestrion and contribs to miss these tags in their spans.

httptrace.TraceAndServe should be able to set these tags, including customization from callers through ServeConfig.