Unified Config object #313
Description
Is your feature request related to a problem? Please describe.
There are many environment variables managed across the codebases and there is a TypeScript Config class here: https://github.com/ethereum-optimism/optimistic-rollup-integration-tests/blob/master/packages/integration-tests/src/config.ts
Having something like this that is fully fleshed out and exported from one of the NPM packages would help to make configuration a lot easier and unified between all of the different repos/tests.
Describe the solution you'd like
A Config class that is aware of all of the environment variables used by the various repos and implements getters for them.
Additional context
There are a few of these Config classes around that are implemented for the env vars it cares about