Add Holesky to e2e tests

[kuzdogan]

We should add the new Holesky testnet to our e2e tests similar to Goerli and Sepolia.

The CI run that does this process is at:

• Nightly tests: https://github.com/ethereum/sourcify/blob/staging/.circleci/nightly.yml
• For staging and master branches: https://github.com/ethereum/sourcify/blob/staging/.circleci/continue_config.yml

The job makes use of the https://github.com/sourcifyeth/metacoin-source-verify project that deploys the contracts.

Can't make this a "good first issue" because it makes use of our Ethereum Account's credentials that can't be exposed externally