Fix wsrelay connection leak (#15113)

- when re-establishing connection to db close old connection
- re-initialize WebSocketRelayManager when restarting asyncio.run
- log and ignore error in cleanup_offline_host (this might come back to bite us)
- cleanup connection when WebSocketRelayManager crash

awx/main/management/commands/run_wsrelay.py

@@ -165,11 +165,10 @@ class Command(BaseCommand):
             return
 
         WebsocketsMetricsServer().start()
-        websocket_relay_manager = WebSocketRelayManager()
 
         while True:
             try:
-                asyncio.run(websocket_relay_manager.run())
+                asyncio.run(WebSocketRelayManager().run())
             except KeyboardInterrupt:
                 logger.info('Shutting down Websocket Relayer')
                 break