Make orderers persistent

[msolefonte]

To prevent orderers from losing their data after a failure or restart, I strongly recommend to add persistence in them by storing the data under /var/hyperlegder/production in a EBS volume.

I do not know how much storage should be required in EBS (perhaps 200GB, as with Kafka), but I would recommend to set that as a variable in env.sh and let the user set it.

As I said in another issues, this is simple to do, I can send the PR if this issue is approved, but it has to be reviewed by another one.

[msolefonte]

PR #13 has been created