feat: create redisha module

- manage redis/sentinel clusters
- ensure ulimit_managed is false
- dynamically find servers in role to identify master
- add redisadm and sentineladm commands
- add script to check if the current host in the master

modules/redisha/templates/check_redis_master.erb

@@ -0,0 +1,2 @@
+#!/usr/bin/bash
+sudo /usr/local/sbin/sentineladm info | grep -q <%= @facts['networking']['fqdn'] %>