Etherlink/Kernel/Tezlink: Introduce more concrete tezos notion in kernel (block, block header)

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!17159 (merged)

What

Between Etherlink and Tezlink stage zero and stage one will be shared overall, but not for stage two here is what should be shared:

• create a block in progress from a blueprint (if not read in the durable_storage)
• call the function compute a block in progress (different for each chain)
• promote the block (a move in the durable_storage and the clean of the delayed transactions)

This is what does this MR by introducing tezlink concept with etherlink existing ones

Why

Introduce tezlink in the etherlink kernel

How

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR