increase per-channel capacity

* 100 is the default capacity for a channel. If the client doesn't read
the socket fast enough, websocket messages can and will be lost. This
increases the default to 10,000

awx/settings/defaults.py

@@ -957,6 +957,7 @@ CHANNEL_LAYERS = {
         "BACKEND": "channels_redis.core.RedisChannelLayer",
         "CONFIG": {
             "hosts": [("localhost", 6379)],
+            "capacity": 10000,
         },
     },
 }