Add marker to request logging of SolrCore#execute

Logs can somethings be a bit too noisy on SolrCore#execute which prints info on each response.

In our usage, `/get` and `/replication` are too verbose that we want to skip logging those 2 while keeping response logging for rest of the requests.

It would be nice to add a "marker" with the path of the request so that user can tune logging behavior per request handler (path).