Ensure daily nonce randomness

### Is your feature request related to a problem?

Currently the daily nonce renewal is created randomly by the first node of the election.
But the daily nonce seed is not verified allowing the first node to manipulate the seed and put a specific one it wants.

### Describe the solution you'd like

We should find a mechanism to ensure the randomness of the seed created by the node.
We could use VRF (Verifiable Randomess Function) to do so.

### Additional context

_No response_

### Epic

_No response_

Start by locating the daily nonce renewal and election implementation in the Elixir repository, then review how the seed is created and verified. Evaluate the proposed VRF approach against the consensus requirements; done means the elected first node cannot manipulate the seed, with tests covering the randomness mechanism and verification.

Written by the indexing model from the issue text.