New consensus: Review hashing schemes and domain separation

**Task description**
This task is to check a few things regarding hashing schemes and domain separation. This is about some of the functions in concordium-node/concordium-consensus/src/Concordium/Konsensus/V1/Types.hs.

**Sub-tasks**
- [ ] Determine if the hashing scheme used in `computeTransactionsHash` is appropriate.
- [ ] Check that the messages bytes in `quorumSignatureMessageBytes` cannot collide with other signed messages.
- [ ] Check that the messages bytes in `timeoutSignatureMessageBytes` cannot collide with other signed messages.
- [ ] Determine if domain seperators should be used in `blockSignatureMessageBytes`.

Start in concordium-node/concordium-consensus/src/Concordium/Konsensus/V1/Types.hs and inspect computeTransactionsHash, quorumSignatureMessageBytes, timeoutSignatureMessageBytes, and blockSignatureMessageBytes. Compare their hashing and signed-message encodings, checking each sub-task for collision and domain-separation concerns. Done means every checklist item has a documented conclusion and any required consensus changes are identified.

Written by the indexing model from the issue text.