Support synthetic-network for simulation

[balqaasem]

synthetic-network is a tool for docker that allows you to simulate different network conditions, like
variable latency, rate limit, etc. Easiest way to manage parameters of a synthetic-network is to use its web-ui - after
executing run_consensus_synthetic-network.sh it should be available at http://localhost:3000 (each node has separate settings
page, i.e. :3001 is Node1, ...).