MongoDB Multi (or 3) nodes performance benchmarking using SBK

[kmgowda]

Describe the Issue (Bug/Feature)
Conduct the performance benchmarking of MongoDB distributed with 3 nodes

To Reproduce

1. create 3 noes MongoDB cluster , refer here 3 node replication setup : https://medium.com/swlh/mongodb-creating-a-3-node-replica-set-cluster-7ca94849b139

Expected behavior
sbk benchmarking with option "-class mongodb" with readers and/or writers should yield performance values

Additional context
refer here for sample benchmarking: https://github.com/kmgowda/SBK/tree/master/driver-mongodb