feat(cast): implement auto gas price adjustment for stuck transactions in cast send

[leovct]

Motivation

Closes #4454

Solution

Implement a new flag called --bump-fee, in cast send, to automatically bump transactions gas price. The idea is to be able to automatically replace stuck transactions during busy network times. Instead of manually adjusting the gas price, the user can specify the --bump-fee flag and cast will automatically adjust the gas price to replace the transaction.

The following safeguards have been implemented:

• A gas price bump limit percentage can be set by the user, by default it it set to 150%. It represents the maximum total percentage increase allowed for gas price. For example, a value of 150 means the gas price will never exceed 150% of the original price (1.5 times the initial price).
• A maximum number of gas price bumps can also be set by the user, by default set to 3.

The gas price increment is also configurable. By default, it is set to 10%, meaning that the gas price will be increased by 10% of the original gas price on each retry.

[klkvr]

nice! just nits for now

so basically --bump-fee is supposed to determine the minimal gas price required to replace the pending transaction once.

I'm wondering if there are any easier ways to do this? e.g there's eth_getTransactionBySenderAndNonce which didn't get wide adoption yet unfortunately, not sure if there's something similar we could use

[leovct]

I removed the bump gas limit percentage in favour of a simpler bump gas limit. It would be great to use eth_getTransactionBySenderAndNonce to retrieve the tx and the base fee from here. Since I can't use that at the moment, I'm always iterating from the initial base fee and thus the percentage calculation was wrong.

[klkvr]

not sure what's the best strategy here, but wondering if we should also bump the priority fee somehow?