Process the replay-dkg-messages operation on the Airgapped machine

[zavgorodnii]

THE PROBLEM (BACKGROUND)

If someone successfully went through the DKG and lost his communication keys and airgapped state, but still has his private bip39 mnemonic, they can not sign any data.

THE SOLUTION (BACKGROUND)

We can scan the topic data for messages from the finished DKG round, provide a mapping from the old communication keys to the new communication keys, build a new Operation for the airgapped machine with both the old messages and the new communication keys — and then process that operation inside the airgapped machine.

THE TASK
— Add a processor for the Replay Operation (generated by the Client, see #135) that replays all operations for a finished DKG round and prepares the Airgapped machine to sign data.
— Write airgapped tests & flow tests.