[legacy-framework] Add support for custom messages and icons in recipes

[ntgussoni]

This is a feature nobody asked for (maybe?) but it's something that I think was missing in the recipes; writing a custom message step while installing a recipe.

Closes: ?

What are the changes and their implications?

Adds new step type printMessage

  builder.printMessage({
    successIcon: "😭",
    stepId: "oops",
    stepName: "Im so sorry :(",
    message:
      "This recipe can't edit your blitz.config.ts (yet), you can add the Blitz Guard middleware following these two steps: https://ntgussoni.github.io/blitz-guard/docs/middleware",
  })

This prints the message in the following way

The updated documentation can be found here: blitz-js/blitzjs.com#508

Bug Checklist

• [ x ] Integration test added (see test docs if needed)

Feature Checklist

• [ x ] Integration test added (see test docs if needed)
• [ x ] Documentation added/updated (submit PR to blitzjs.com repo)