chore: add a create-repos script

[DSchau]

This PR introduces a create-repos script which will likely be used
either manually, or as part of some CI process relating to #10310, e.g. on master push and examples/* change, run this script.

I've made some assumptions here, specifically:

• examples are starters, and we can create the repo gatsby-starter-*
  for every example
• using-* should be replaced, e.g. using-styled-components should
  become gatsby-starter-styled-components
• that it makes sense to install dependencies for scripts and add them
  to the yarn workspace

I think these all make sense, but sanity check appreciated.

[DSchau]

General idea is we'd (probably) run this in CI like so:

node scripts/create-repos --token hunter2

which would output the following (if run for the first time)

Created the following repos:
  - gatsbyjs/gatsby-starter-client-only-paths
  - gatsbyjs/gatsby-starter-feed
  - gatsbyjs/gatsby-starter-gatsbygram
  - gatsbyjs/gatsby-starter-hn
  - gatsbyjs/gatsby-starter-image-processing
  - gatsbyjs/gatsby-starter-no-plugins
  - gatsbyjs/gatsby-starter-no-trailing-slashes
  - gatsbyjs/gatsby-starter-simple-auth
  - gatsbyjs/gatsby-starter-sitemap
  - gatsbyjs/gatsby-starter-styleguide
  - gatsbyjs/gatsby-starter-asciidoc
  - gatsbyjs/gatsby-starter-contentful
  - gatsbyjs/gatsby-starter-css-modules
  - gatsbyjs/gatsby-starter-csv
  - gatsbyjs/gatsby-starter-cxs
  - gatsbyjs/gatsby-starter-drupal
  - gatsbyjs/gatsby-starter-emotion
  - gatsbyjs/gatsby-starter-emotion-prismjs
  - gatsbyjs/gatsby-starter-excel
  - gatsbyjs/gatsby-starter-faker
  - gatsbyjs/gatsby-starter-gatsby-image
  - gatsbyjs/gatsby-starter-gatsby-source-graphql
  - gatsbyjs/gatsby-starter-glamor
  - gatsbyjs/gatsby-starter-hjson
  - gatsbyjs/gatsby-starter-javascript-transforms
  - gatsbyjs/gatsby-starter-jest
  - gatsbyjs/gatsby-starter-jss
  - gatsbyjs/gatsby-starter-local-plugins
  - gatsbyjs/gatsby-starter-medium
  - gatsbyjs/gatsby-starter-mobx
  - gatsbyjs/gatsby-starter-mongodb
  - gatsbyjs/gatsby-starter-multiple-providers
  - gatsbyjs/gatsby-starter-page-loading-indicator
  - gatsbyjs/gatsby-starter-page-transitions
  - gatsbyjs/gatsby-starter-path-prefix
  - gatsbyjs/gatsby-starter-prefetching-preloading-modules
  - gatsbyjs/gatsby-starter-redirects
  - gatsbyjs/gatsby-starter-redux
  - gatsbyjs/gatsby-starter-remark
  - gatsbyjs/gatsby-starter-remark-copy-linked-files
  - gatsbyjs/gatsby-starter-sass
  - gatsbyjs/gatsby-starter-sqip
  - gatsbyjs/gatsby-starter-styled-components
  - gatsbyjs/gatsby-starter-styled-jsx
  - gatsbyjs/gatsby-starter-styletron
  - gatsbyjs/gatsby-starter-stylus
  - gatsbyjs/gatsby-starter-typescript
  - gatsbyjs/gatsby-starter-unstructured-data
  - gatsbyjs/gatsby-starter-wordpress

[DSchau]

You can also run it ad hoc like so:

node scripts/create-repos --token hunter2 --repos example --repos other-example

[DSchau]

Left some comments 👇

[DSchau]

Longer term - I think this will be consolidated into just starters. I don't see the point of differentiating the two.

[DSchau]

Added this so that running yarn in the root will also install any additional deps for scripts. Think this makes sense.

[KyleAMathews]

I like the idea of making many of the examples starters but some of them really are just examples. You'd never use them to build a site but they'd be great to install and play around with.

[KyleAMathews]

So gatsby-starter-emotion makes sense but gatsby-starter-page-transions doesn't.

[DSchau]

@KyleAMathews so I see a few solutions for that:

1. We keep starters/examples separate (don't love this)
2. We move all examples/starters into one folder, e.g. examples -> starters, and then use metadata to denote a starter

I don't love how it's not super discoverable, but it does solve the problem fairly well.

package.json in examples/using-styled-components

{
  "name": "gatsby-example-using-styled-components",
  "private": true,
  "description": "Gatsby example site using the styled components plugin",
  "version": "2.0.0",
  "keywords": [
    "gatsby",
    "gatsby-starter"
  ]
}

What do you think?

[KyleAMathews]

Thinking about this more, it's not really clear how distinguishable examples are from starters. What makes for a good starter vs. example? We've traditionally said starters are use case focused while examples are small isolated sites that demonstrate using a particular tech or site building technique. But like the example of emotion. Why wouldn't someone just use gatsby-starter-emotion as the start of their site if they know they'll want to use emotion?

Maybe just calling them all starters is easier 🤷‍♂️

[KyleAMathews]

Themes are a way better "starting point" than starters anyways as they can be upgraded and functionality is encapsulated and hidden better. All starters are basically example sites I guess really.

[KyleAMathews]

@DSchau this can be closed right?