* op-node: Generic Commitment

This is a generic commitment to be used by the op-node & op-batcher.

* abstract commitments to CommitmentData interface

* correct byte-stripping ; add tests ; finish wiring

* make GenericCommitment always verify

* correct action tests

* PR comments

* fix unit test

* remove fmt.Println

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Co-authored-by: Joshua Gutow <jgutow@oplabs.co>