feat(create-gatsby): Add Tailwind as a styling choice

[ChrisLaRocque]

Description

This change adds Tailwind as an option to the list of styling choices when running npm init gatsby

For this new functionality was added to the shape of the questionare:

• isGatsbyPlugin can be used to not add the key of the object to the plugins list
• files to write files inside the stubs folder to the user's project

Documentation

N/A

Tests

Build the CLI locally and then run it somewhere else with Node

Related Issues

N/A

[LekoArts]

The PR is too much of a one-off and needs to be more generic. All the definitions must reside in questions/styles.json as that's the source of truth

My changes were addressed