Infura API key is exposed

https://github.com/cloudflare/cfweb3/blob/c4e627627732edfadcaccd90b5656b0b3c54c43c/contract/hardhat.config.js#L22

Its probably very unlikely that the Infura account that is linked to this key is _not_ on the free tier but on the small chance that it is, someone could use it for their own nefarious purposes.

Suggestion:
There could be added documentation for a user to set up an Infura account to get their own API key and possibly use dotenv instead to handle environment variables. Let me know what y'all think and I could open up a PR :)