* feat[contracts]: replace Lib_RingBuffer with a simpler Lib_Buffer

* chore: changeset

* test: add tests for Lib_Buffer

* lint: fix

* test: add extra coverage for Lib_Buffer

* Update packages/contracts/contracts/optimistic-ethereum/libraries/utils/Lib_Buffer.sol
Co-authored-by: ben-chain <ben@pseudonym.party>

* add some extra comments
Co-authored-by: ben-chain <ben@pseudonym.party>