ParisB has demonstrated the Smart Rollup commitment logic is not resilient to commitment period constant changes, forcing us to release Octez 20.1 to activate ParisC. The underlying logic error is well explained in ParisC announcement, but in a nutshell, the reason can be summarized as follows: in ParisB, the new constants is used in place where the previous one should.

This patches addresses the root issue, but keeping track of past commitment periods (starting from ParisC).

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Proto: Consider past periods to decide the next commitment level

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