Add chainlink functions guide

[MattPereira]

Overview

Quick start for using chainlink functions to fetch off chain data from an API and do something with the response on chain

Items

• Create contract that consumes chainlink functions
• Script the upload of apiKey secret to github gist and encode the url for use as arg in sendRequest
• Create showcase on frontend to display some feedback to user that incorprates the response from chainlink

Resources

• https://functions.chain.link/
• https://github.com/smartcontractkit/functions-toolkit/blob/main/README.md
• https://github.com/smartcontractkit/functions-toolkit?tab=readme-ov-file#storing-encrypted-secrets-in-gists
• https://github.com/smartcontractkit/functions-toolkit?tab=readme-ov-file#off-chain-hosted-secrets
• https://github.com/smartcontractkit/functions-toolkit?tab=readme-ov-file#functions-encrypted-secrets-management
• https://docs.chain.link/chainlink-functions/tutorials/api-use-secrets-gist

Debugging

• verified that on chain secret is good
• verified that zipCode arguments are good
• no fucking idea why the Functions.makeHttpRequest is failing 😢