Increase default ping timeout to 10 seconds

During periods of poor connectivity, the ping timeout of 2 seconds
can easily be exceeded, especially with ENet's RTO backoff active.

This causes an unnecessary disconnection when the connection would
have recovered on its own in a few seconds. Increasing the timeout
to 10 seconds should prevent spurious disconnections in most cases.

assets/sunshine.conf

@@ -78,7 +78,7 @@
 # ]
 
 # How long to wait in milliseconds for data from moonlight before shutting down the stream
-# ping_timeout = 2000
+# ping_timeout = 10000
 
 # The file where configuration for the different applications that Sunshine can run during a stream
 # file_apps = apps.json