Visual Test Addon Onboarding behind query param

[weeksling]

Resolve AP-4116, AP-4126, AP-4127, AP-4133, AP-4115, AP-4110

This adds addon onboarding, with steps:

• Initital Build flow - to prompt brand new projects to create a first build baseline before testing changes.
• Make a Change flow - force the user to create a local change, and run a local build to test for changes. (will rerun if the build does not have any changes caught).
• Done screen - displays if the last build did have changes, and prompts user to continue to guided walkthrough.
• Guided Tour - once a build exists with changes, guide the user through the story filters, review screens, accepting a story, and rerunning builds.

To enable the onboarding, add the &vtaOnboarding=true query param to your storybook url.

To test, you will want to try this out in these different scenarios:

1. Create a brand new project on Chromatic (no builds) and add the addon. Onboarding will guide you through creating very first build, making a change, and then the guided tour.
2. Add the addon to a project with existing builds on Chromatic. Onboarding will skip ahead to make a change and running second build.
3. Opening a branch with an existing build that has changes. Onboarding will show you the Done screen, and then begin the guided tour (this will be updated to skip ahead to the guided tour without the done screen. Was kept to get a version of the onboarding out - this is a less common edge case).

📦 Published PR as canary version: 1.0.1--canary.144.53a44d0.0

✨ Test out this PR locally via:

npm install @chromaui/addon-visual-tests@1.0.1--canary.144.53a44d0.0
# or 
yarn add @chromaui/addon-visual-tests@1.0.1--canary.144.53a44d0.0