Scrappy settings Id check

[albchu]

What are you adding in this PR?

Demo check for lunch and learn.

This check will verify validity of settings IDs.

June 3rd: This check only validates local settings IDs for now. Can be built upon later if we want to make it more versatile.

What did you learn?

Theme files are parsed from top down. If the schema is defined after the settings path, we need to wait till it has been traversed before we may cross reference these pieces together. In order to validate usages of settings IDs within the schema settings, we can only do this once the file has been completely parsed.

Before you deploy

• [ ] This PR includes a new checks or changes the configuration of a check
  • [ ] I included a minor bump changeset
  • [ ] It's in the allChecks array in src/checks/index.ts
  • [ ] I ran yarn build and committed the updated configuration files
    • [ ] If applicable, I've updated the theme-app-extension.yml config

• [ ] I included a minor bump changeset
• [ ] My feature is backward compatible

• [ ] I included a patch bump changeset