Improve L1 interop and add testing (consensus.mligo)

I think it would be a good task for both learning about deku and L1/L2 to make him "refactorize" the consensus.mligo, mainly :
rename it

About `consensus.mligo`:

- [x] Move smartcontract from `src/tezos_interop/` to `layer1/bridge`
=> to have clean separation btw L1 interop and L2 interop, i would like to have only deku L2 in src/
=> It's ratger a bridge than a consensus so we put a more meaningful name

- [x] Split the contract in modules
=> easier reading / maintenance; take ligolangs https://github.com/ligolang/advisor-cameligo or any cameligo template as architecture exemple

- [ ] Add unit & mutation tests with ligo framework

- [x] Add contract metadata (read TZIP-12)

- [x] Adapt every script / e2e tests