Add/remove worker nodes on-demand

[nugaon]

There is a need to add or remove worker nodes from the cluster on-demand.

The script should add Bee node(s) to the running cluster, but the bee version can differ from the other running nodes.
Removing docker node can happen via docker container stop <worker-node-name>, but optionally, a script can be written for this use-case in the package.json.

This change will allow to test Swarm network with mixed versioned Bee nodes which is closer to the reality.

[nugaon]

should be addressed after #66