[FEATURE] Sequencer admin contract to encapsulate keys (and namespace) within execution client state root

## Is your feature request related to a problem? Please describe.

Yes, we would like to encapsulate the public key of the sequencer within the state root of the execution client to avoid having to validate it independently for proving state transition and data availability.

Furthermore, this design lends itself to support key rotation for the sequencer software. Which is an issue independent of this, but it would be great to kill two birds with one stone.

## Describe the solution you'd like

Spoke with @tac0turtle about requesting the state root to include the sequencer's public key as well as the namespace it posts data to.

He mentioned that it could be possible to use existing staking contracts.

## Describe alternatives you've considered

Currently we verify the namespace and public key of the sequencer independently of the execution client state root. But ideally we can reduce it to only the state root if those fields are encapsulated within it.

## Additional context

n/a

Aucun fichier, test ou point d’entrée n’est identifié dans l’issue. Commencez par examiner comment le execution client state root est actuellement lié au sequencer namespace et au public key, puis vérifiez si les staking contracts existants pourraient représenter ces champs ; le travail est terminé lorsqu’une implémentation convenue permet au state root de fournir les deux valeurs et prend en charge la modification de validation proposée.

Rédigé par le modèle d'indexation à partir du texte de l'issue.