add maintenance flag to cli topology

[caffeinated92]

This PR is adding maintenance column at the last position within cli topology

replication-manager-cli topology will resulting to:

./replication-manager-cli topology --cluster=fr
####
                 Id            Host   Port          Status   Failures   Using GTID         Current GTID           Slave GTID             Replication Health  Delay  RO MAINT
db8333316815677374852      172.17.0.2   3306          Master          0           No                0-1-5                                                          0 OFF     N
db3425150372194902490      172.17.0.3   3306          Failed       2159           No                0-1-5                0-1-5                                     0  ON     Y
db2995596438658588357      172.17.0.4   3306          Failed       2255           No                                                                               0         N