Improve logging for Exonerator
When looking at #24534 (moved) I noticed there is hardly any useful logging. Both backend and web-frontend need better logging. The web-part has no logs so far and the logs of the backend consist mainly of one message, which should rather be on debug than info level:
INFO o.t.m.e.QueryServlet:315 Returned a database connection to the pool after 105 millis.