Improve commands to run storybook

[ad9242]

Summary

Improve the commands in the root package.json to not default to opening 4 instances of storybook.

💬 Description

Since the addition of the canary packages, doing a npm run storybook in the root folder results in 4 storybook instances being run. This is a big drain on system resources and arguably not particularly useful.

Possibly there could be 2 commands: 1 to run the web-components & react versions 1 to run the canary versions

Open to other ideas on how to resolve

After making these changes, the contributing.md file should be reviewed to ensure the instructions there are still correct

[MI6-255]

Add a command to run storybook:core