CDDL spec for the wire protocol

[coot]

We need end-to-end wire protocol format for node-to-node and node-to-client protocols.
This is needed to help the ecosystem to develop tools and integrate with Cardano, without relying on Haskell libraries developed by @input-output-hk.

• mulitiplexer binary format
• specification of each mini-protocol which includes hard-fork and ledger structures

Currently we only have specification of the multiplexer binary format, specs of ledger structures. We only have a partial and misleading spec of each mini-protocol messages. This is due to relaying on parametric polymorphism (the networking code knows close to nothing about transactions, headers and blocks), while developers are looking for a concrete syntax. There's also a gap of lack of CDDL for the hard fork combinator developed by the consensus team.

[coot]

Subsumed by #5049.