Create a SIP that empowers protocol/dapp devs to provide end-users with ideal gas params / txn fee controls on a per-network basis

# Context

- Responsibility for network support / network UX on MM side currently split between Confirmations team and Assets team.

- "Our gas logic should be more easily extendable so we can hopefully no longer be gatekeepers to networks having an optimal UX"

- "Until then, we have to manually add networks/custom logic"

- "We’re trying to get away from being a gatekeeper as soon as possible"

[internal link to ad-hoc slack convo](https://consensys.slack.com/archives/GTQAGKY5V/p1706202142962389)

# Overview / Ideal Outcomes

Networks should be able to better handle gas / txn fee logic on behalf on their users via a Snap.

This will result in better experience for:

- end-users who currently face unideal experience on EVM networks if their transaction fee parameters / structure differs from Ethereum

- network/protocol/core developers who have to chase MetaMask to update fee handling every time they update something

- dapp developers who are reliant on MetaMask to support and update various networks

- MM developers who are currently inadvertently gatekeeping ideal network support/experience and thus have to keep track of all the networks and their various fee structures and logic

- adjacent / enablement teams who currently have to play biz dev games with protocol/dapp devs who are trying to get get permission from MetaMask so their users txn's dont fail / suck.

# tl;dr

> :meow_grumpy: –rekmarks

Start with the issue's Context and Ideal Outcomes, then review the linked internal Slack discussion for the missing requirements. Done would be an agreed SIP defining how networks or dapps provide per-network gas and transaction-fee controls through a Snap.

Written by the indexing model from the issue text.