@W-17618443 Extensibility tutorial documentation

[kevinxh]

Description

This PR adds a tutorial.md file for extensibility feature.

Types of Changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Documentation update
• Breaking change (could cause existing functionality to not work as expected)
• Other changes (non-breaking changes that does not fit any of the above)

Breaking changes include:

• Removing a public function or component or prop
• Adding a required argument to a function
• Changing the data type of a function parameter or return value
• Adding a new peer dependency to package.json

Changes

• (change1)

How to Test-Drive This PR

• (step1)

Checklists

General

• Changes are covered by test cases
• CHANGELOG.md updated with a short description of changes (not required for documentation updates)

Accessibility Compliance

You must check off all items in one of the follow two lists:

• There are no changes to UI

or...

• Changes were tested with a Screen Reader (iOS VoiceOver or Android Talkback) and had no issues
• Changes comply with WCAG 2.0 guidelines levels A and AA
• Changes to common UI patterns and interactions comply with WAI-ARIA best practices

Localization

• Changes include a UI text update in the Retail React App (which requires translation)

[adamraya]

nit: Should we use a NPM tag instead like extensibility-preview-latest and point that tag to the latest extensibility preview instead of using 4.0.0-extensibility-preview.3?

We probably will do at least one more release fixing bugs before beta so the version will most likely 4.0.0-extensibility-preview.4

[kevinxh]

Good call, let's create the tag first and then we can update the docs.

[adamraya]

See: #2256 (comment)