CLI - Add --wrapper-envs option to build, codegen, docgen and test

[pileks]

Remaining work

Comments from 28.11.2022. dev sync

• add support for YAML in addition to JSON
• parse tokens for and load env variables
  • This is achieved in the same manner that the deploy command parses and imports env variables.
• Update CLI reference documentation

Description

This PR aims to give developers a quick and easy way to specify wrapper envs when running CLI commands that support the -c, --client-config option.

For example, in order to use a non-throttled Infura API key inside the Ethereum Plugin, you can create an envs.json file like such:

{
  "ens/ethereum.polywrap.eth": {
    "connection": {
      "node": "https://mainnet.infura.io/v3/your_api_key",
      "networkNameOrChainId": "mainnet"
    }
  }
}

and run a command specifying that file:

polywrap codegen --wrapper-envs ./envs.json

Additional notes

A change was made to the Ethereum Plugin in order for it to properly consume the supplied env, with some comments added as to the reasoning behind the change. The change does the trick, but I feel like we should do a more detailed review as to why we are using the approach we are currently, and maybe set up a more robust solution.