Coinbase Thresholds and Amounts

[whoabuddy]

The coinbase thresholds and amounts were originally scoped out such that:

• only the auth contract could update them
• the auth contract was hard-coded to update the token contract
• the auth contract then called the core contract to update, which pulls from the token contract

In the new protocol, I think it makes sense to migrate this into an extension, which we could initially load up using a proposal and the current CCIP-008 values from the token contract.

The downside is if things are updated in the future, the data in the token contract and the extension wouldn't match.

At this time the only contract using that data is the current core contract (which would be disabled), but opening this to think through some different options as well.

edit: future token contracts could exclude the coinbase information, so this would only be an issue for MIA/NYC in current form