Vault cluster set capacity_rebalance default to false

to match the default non-configured value setting the default capacity_balance to false.

Vault cluster protect_from_scale_in

Provide variable to control auto scaling group protect_from_scale_in. Default to false in order to replicate the default behavior of the autoscaling group.

Vault cluster min_size made smaller

vault cluster min_size make smaller

min_size cluster will now be calculated as `(({cluster_size}/3)+1)`