[ntcore] Revamp listeners (#4511)

- In both C++ and Java, add listener functions to Instance class (same as NT3 provided)
- Add WaitForListenerQueue functions (same as NT3 provided)
- Move Java non-poller implementation to Instance (previously only handled single instance)
- Change C++ listeners to take non-const references for subscribers etc to help avoid footguns from use of temporary objects (also add doc comment)
- Fix Preferences making .type persistent

ntcoreffi/src/main/native/symbols.txt

@@ -220,6 +220,9 @@ NT_StopServer
 NT_Subscribe
 NT_Unpublish
 NT_Unsubscribe
+NT_WaitForConnectionListenerQueue
+NT_WaitForTopicListenerQueue
+NT_WaitForValueListenerQueue
 WPI_CreateEvent
 WPI_CreateSemaphore
 WPI_CreateSignalObject