Figure out and clean up contract artifacts loading

[krebernisak]

Currently, we don't have proper tools in place to load Cairo and Solidity contract artifacts from imported NPM/PyPI packages.

Our typescript tests and gauntlet implementation is filled with ad-hoc loading functions like this:

export const loadOpenzepplinContract = (name: string): any => {
  return json.parse(
    fs
      .readFileSync(
        `${__dirname}/../../../node_modules/@openzeppelin/contracts/build/contracts/${name}.json`,
      )
      .toString('ascii'),
  )
}

There are many unanswered questions:

• Is loading Solidity contracts from imported NPM packages really still unsupported by the HardHat toolchain?
• If it's not supported, what kind of additional utilities we can write to simplify this for us?
• What about Cairo imported contracts? These can be loaded to scope via NPM or PyPI, which complicates things.
• What about our Go stack, how do we access and load contracts from our Go code?
  • We currently proxy contract deployments and some interactions via Gauntlet (TS). Will we continue to do that for all cases or will we need to access contract directly from Go code?