Optimistic module integration

[theochap]

Description

This PR aims to add an end-to-end integration workflow for the optimistic module. The main changes are concentrated in SlotData and the ChainState module. The slot data is now equipped with a namespace method that returns the slot's namespace which is used to update the chain-state module and skip the transactions that did not come from the default namespace. The Namespace is also integrated in the context as an associated type. The rest of the workflow is left unchanged.

Testing

An end-to-end integration test is going to be added.

[cemozerr]

Can we close this PR now @preston-evans98?

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