Proto, SCORU: RPC combinations to retrieve from the LCC all the commitments and their given stakers level by level

Context

Note that this MR will most likely need a backport to M protocol.

#4535 (closed) (requoting what was written in the issue:)

Since a staker now stake on a commitment rather than on a branch, it can stake on multiple commitments at a time, one per inbox level, therefore, the commitment to retrieve the commitment associated to a staker for a given rollup must now be retrieve the commitments associated to a staker per level for a given rollup.

To do it properly, with the constraints given by what we have in src/proto_alpha/lib_protocol/storage.ml, we need an rpc that:

• returns the commitment list for a given inbox level

• returns the list of stakers' indexes for a given commitment

• returns the list of stakers' public key hashes for a given rollup id

• returns the stakers' index for a given stakers' public key hash

This way we will be able to retrieve from the LCC, all the commitments and their given stakers level by level.

Manually testing the MR

CI

Checklist

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