feat: super root withdrawal proofs

[smartcontracts]

Introduces a proposal to include super root validation logic inside of the base optimism portal contract.

[smartcontracts]

Review notes

• Include sequencing of events in the design doc
• Maybe consider switching methods based on game type
• MUST have Chain ID in the Portal to prevent x-chain withdrawals
• Strong preference that everyone is using Super Roots ASAP

[smartcontracts]

Launch sequence is described in this separate design doc: #207

[clabby]

I agree with this proposal, and it should still be able to use all of the logic from my PR.

Good catch on including the chain ID in the portal.

I'd still like for us to explore using the game type as the activation method for the proof verification functionality. It feels much nicer for this to be implicitly activated, rather than having to switch the game type + explicitly activate super root verification. We never ran into this need because we've never switched the format of the output root before, but being able to have games declare their withdrawal inclusion proof verification function is beneficial.

If we don't want to do that, this should still be fine, and we can always upgrade to that later.