[Project - Onboarding]: Create a new addon @storybook/addon-onboarding

[valentinpalkovic]

Description:

Set up a new @storybook/addon-onboarding addon, which doesn't do anything. This task aims to set up a blank addon on which we can start to work. Set the addon up in a separate repository.

Acceptance criteria:

• Plain addon is set up and pushed
• CI is configured to use "auto" for publishing the npm package
• Remove any dummy panel/tab/... registrations when using the addon-kit (The addon shouldn't do anything!)
• Addon is published to npm

[valentinpalkovic]

The addon is available here: https://github.com/storybookjs/addon-onboarding