Add support for redis cluster (#3670)

bungee/src/main/resources/config.yml

@@ -260,6 +260,7 @@ broadcast-received-log-entries: false
 
 # Settings for Redis.
 # Port 6379 is used by default; set address to "host:port" if differs
+# Multiple Redis nodes can be specified in the same format as a string list under the name "addresses".
 redis:
   enabled: false
   address: localhost