Disable Master failback in Galera Monitor

Disable Master failback in Galera Monitor
Added 'disable_master_failback' monitor option

Added 'disable_master_failback' option in Galera monitor
Merge branch 'develop' into MAX-316
Added Master Failback in show monitors

Added Master Failback in show monitors
Branch update

Branch update
Merge branch 'MAX-316' into develop