Explore: remove message persistence from network layer

[ffakenz]

This eliminates message storing/reading from disk.

Explores #1417

Failing CI demonstrates:

• all hydra-node tests pass besides the network-resilience ones, which is expected.
• curren hydra-cluster benchmarks just don't work anymore.
• no network-test passed.

Conclusion: #1417 is not a solution to our problem, but it significantly increased the system's speed.
This leads us to question whether we should persist all network messages in any future solution.

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• CHANGELOG updated or not needed
• Documentation updated or not needed
• Haddocks updated or not needed
• No new TODOs introduced or explained herafter

[ch1bo]

I concur with your conclusion @ffakenz and we should close this PR and #1417 with "not planned"

[ffakenz]

Closing because #1417 is marked as "not planned"