Scalable Bee nodes

[nugaon]

Currently, it is possible to have only maximum 5 nodes in a bee-factory network, because there wasn't any JS lib that could generate swarm.key format key, thereby, there were pre-generated swarm keys for 5 nodes.

The new V3 compatible keys in Bee opened the gate to generate V3 format keys for nodes with a JS lib (or with swarm-cli). These keys can be placed into the keys folder under each Bee data dir before spinning up the Bee instances with docker.

It allows to import/handle the keys easily in other environment and have tests more interactive.