Ability to construct connection uri for Mongo replicasets

[pradeeban]

Currently, it is assumed as host:port, which is not the case for replicasets. Replicasets assume the format of host1:port1,host2:port2,host3:port3

Probably we need to get as input the whole url rather than asking for a host and port and then constructing the url in Bindaas.
https://docs.mongodb.com/manual/reference/connection-string/