Create `init` functionality to set up Storybook structure

[haldunanil]

Possibly outsource this to cookiecutter?

Directory structure:

• /.storybook
  • addons.js/ts
  • config.js/ts
  • webpack.config.js/ts
• /src
  • @ types
    • markdown
      • index.d.ts
  • /components
  • /styles
  • /util
    • index.js/ts
  • index.js/ts
  • index.stories.js/ts
• /tests
  • .eslintrc
  • jest.setup.js/ts
  • jest.transform.js/ts
• .gitignore
• README.md
• CONTRIBUTING.md
• rollup.config.js
• tsconfig.json
• tsconfig.test.json
• tslint.json
• package.json