* op-deployer: Custom gas price estimator

Sepolia's fees are super high and extremely volatile right now. As a result, it became difficult for users to deploy new chains using op-deployer. The OPCM's deploy transaction buys most of the gas in the block, and the default gas price estimation logic in the transaction manager wasn't aggressive enough for the transactions to land on chain in a timely manner.

This PR adds the ability to customize the transaction manager with a custom `GasPriceEstimator` function that returns the tip, base fee, and blob fee. I extracted the original logic in the transaction manager into a default estimator that will be used if one isn't specified. For op-deployer, I built a custom estimator that pads the head block's base fee by 20%, and multiplies the suggested tip by 10. After testing this, I was able to get transactions onto Sepolia reliably. The algorithm is pretty simple and overpays for transactions by a lot, but for op-deployer's use case it's more important that transactions land quickly than it is they be cheap. Deployments are a one-time thing.

* code review updates

* better default support

* specific test for extension