op-node integrate shutter-node and engine-API changes

[ezdac]

The op-node consensus client has to be modified to integrate with the shutter op-geth execution client as well as the external shutter P2P integration (see #9) .

• implement the different behaviour of the Engine API requests depending on shutter mode (active, inactive, deactivation)
• Implement the failure handling logic described in OP node shutter state machine #7
• tbd: allow to use the shutter op-node with rollups that do not implement shutter (optional)