Implement the `require_auth` option in the server.  A previous commit
erroneously added the `require_auth` option to the `server.cfg` file,
which had not yet been implemented in the server at the time.  This
commit solves this issue by checking that option.

This commit also changes some action names which were previously unused
for clarity.

@@ -177,2 +190,4 @@
 }
 
+// Returns the packet action string for the given JSON bytes.
+func getPacketAction(jsonBytes []byte) (string, error) {