* maint(ct): clean up OptimismPortal contract

Cleans up and standardizes the OptimismPortal contract.

* feat(ct): implement EIP-1559 gas burn

Implements the EIP-1559 gas burn in the OptimismPortal using Joshua's
specification. Simplified the initial draft by Mark quite a bit at the
expense of slightly increased gas costs.
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Mark Tyneway <mark.tyneway@gmail.com>