[Constitutional] AIP: Transition Arbitrum One ordering policy to Priority Gas Auctions (PGA)

This proposal, a Constitutional Arbitrum Improvement Proposal (AIP), aims to replace the current transaction ordering system called Timeboost on Arbitrum One with a new mechanism called Priority Gas Auctions (PGA). PGA will allow users to pay a priority fee to get their transactions processed faster, similar to how other blockchains handle transaction priority. It also proposes to disable Timeboost on Arbitrum Nova. The new system will sort transactions based on these priority fees in 125ms rounds before publishing a block every 250ms, and includes a mechanism to prevent transactions with low or no priority fees from being indefinitely delayed.