feat: consensus mechanism to write to the CAS/ledger

Problem

Currently, writing to the ledger of the network is a process that is not synchronized. That is to say that there is no consensus between the peers, and as such data could be lost during the process as multiple actors could try to write at the same time to the ledger - and only one of them would win. This is a problem because we cannot guarantee data integrity, and moreover, since we want to have a CAS ( https://github.com/masa-finance/masa-oracle/issues/381 ) this would lead to invalid data across the nodes.

Proposed solution

As a first pass, we could implement raft consensus among the peers. There is already a well known library ( https://github.com/libp2p/go-libp2p-raft ) which can work with libp2p to have a basic raft consensus.

The idea is to have raft to guarantee that there is only one leader in a specific moment that can write to the ledger, and all the other nodes would have to accept new blocks only by the leader.

Additional context

See also an example of using raft and libp2p here: https://github.com/mudler/go-libp2p-simple-raft

Acceptance criteria

[ ] Nodes should agree on leadership before trying to attempt to write to the network
[ ] only the leader will write new blocks to the network when needed
[ ] new blocks are going to be accepted by the peers only if written by the current leader
[ ] the leader should accept data to write on the ledger by other nodes via libp2p protocol
- [ ] if non-leader nodes needs to write data, they should try to acquire leadership, or send the data to the leader

masa-finance / masa-oracle