Updating @glimmerx/storybook to Storybook-v6

[aroskar]

Changes include:

• Fix for the storybook app run command to run on basic-example-app and not on example-app
• Updating @storybook/* packages to v6.x
• Changes to handle the backwards incompatible changes in Storybook v6
• Changes to use the new features from Storybook v6 in the basic-example-app
• Adding a story in Component Story Format (CSF)

Backward incompatible changes required by @glimmerx/storybook consuming apps:

• Apps no longer need the {APP_ROOT}/.storybook/config.js storybook configuration file.
• Instead the consuming app will have to setup the configuration in {APP_ROOT}.storybook/main.js.

For example:

module.exports = {
  stories: ['../src/**/*.stories.@(js|ts)'],
  addons: ['@storybook/addon-essentials']
}

For more details: https://storybook.js.org/docs/react/configure/overview#configure-your-storybook-project

Testing done:

• Ran yarn test
• Ran yarn storybook and tested the stories. Please check screenshots in this PR.

Screen Shots:

Rendering the Stories in CSF

Storybook v6 docs