Make the recursive query_lookup() call from query_gotanswer() async
According to the perfdata, when the query_cname() calls are chained they can consume quite a lot of time inside the worker thread increasing latency for all other waiting queries.
Make the query_cname(), query_dname() and query_coveringnsec() calls from query_gotanswer() asynchronous, so the multiple recursive calls doesn't block other clients.
Closes #4185 (closed)