[FEAT] Add a protection layer to MTE wallet pk storage to mitigate risks

[zerohex-eth]

Add a protection layer to MTE wallet pk storage

Description

MTE wallet is an empty wallet used to propose transactions on a Safe as a delagate.
An additional layer of protection for private key management is needed to mitigate the risk of spamming multisigs with unwanted transactions.

Proposed Solution

@jigglyjams
OZ has a suite of products called Defender and one of the sub products is called Relay. This gives you a managed wallet where the keys are managed by some AWS key managment service (I think AWS KMS). You can easily revoke and API key if it get compromised and not have the private key compromised
https://docs.openzeppelin.com/defender/relay

Source

merge-to-earn/utils/initContracts.ts

Line 27 in 91e85cf

export const mteWallet = new ethers.Wallet(String(process.env.PK))