When a highly inefficient query is done, vertx main thread is blocked

Main thread blocking causes module to become inaccessible and poses a threat to other simultaneous requests.

Steps:
1. Execute CQL included in attachment expecting 350k+ results
2. Note message reporting [vertx-blocked-thread-checker] BlockedThreadChecker Thread Thread[vert.x-eventloop-thread-1,5,main] has been blocked for 28661 ms, time limit is 2000 ms
3 Note that Health checks also fail during this time, leading to module appearing to be unavailable

Module should not block main thread when waiting for slow query.

URL:
mdriscoll