eth2 tests integration

[fjl]

This issue is about integrating eth2 clients into hive.

hive changes:

• think about port 8545 check
  • docker health check?
  • provide lower level non-blocking client startup in sim api
    • make the simulator poll
  • just make it work in eth2 client images with this port
• enode.sh is eth1 specific
  • no need to worry about it because eth2 has a standard API for this
  • there should be a way to get the multiaddr in eth2
• need way to access files of running container or run script in container
  • i would prefer script approach, in the following way
    • client has defined directory /hive-bin/ containing scripts
    • sim API will only launch scripts in this directory

eth2 specifics:

• eth2 has two roles:
  • beacon node
  • validator node
• we need to package both, e.g. clients/eth2-validator/prysm, clients/eth2-beacon/teku
• eth2 rest API needs to be started by client
• want to test validator key move between client instances, because its complicated w.r.t slashing

env:

• eth2 spec configurables
• bootnodes
• node identity (maybe make this optional)

files:

• genesis file (ssz)
  • deposits
• validator keys (json)