Linear task: ENG-3229.

Now that we're using getCommConfig, these API keys can be specified with JSON files in keyserver/secrets instead of requiring patching package.json files with env var declarations.

Depends on D7354

1. I created a valid keyserver/secrets/alchemy.json file
2. I added a console.log to print the value of alchemyKey from getConfigs in lib/webpack/shared.cjs
3. I made sure that it printed the right value when called from landing and web, in both dev and prod modes

I also made sure to set the corresponding env var on my production keyserver.