chore: Port FreeSewing.dev to docusaurus

The replaces the NextJS site powering FreeSewing.dev with a Docusaurus
setup. It's part of my efforts to simplify FreeSewing's setup so we can
focus on our core value proposition.

sites/dev/docs/howtos/environments/nodejs/readme.mdx

@@ -0,0 +1,95 @@
+---
+title: FreeSewing in Node.js
+---
+
+These instructions explain how you can generate patterns in Node.js.
+Whether it's in a backend application or on the command line, all
+it takes is a few lines of code — and a couple of dependencies — to
+generate a pattern.
+
+:::tip
+
+##### Use FreeSewing.org if you just want a pattern
+
+These instructions are intended for people who want to generate
+their own patterns using FreeSewing packages.
+If you _just want a sewing pattern created for you,_
+you can get all our designs on [FreeSewing.org](https://freesewing.org/),
+our website for makers.
+
+:::
+
+## High level overview
+
+To generate a pattern, you will need to:
+
+- Instantiate the pattern (`new ...`)
+- Pass it the settings and measurements you want to use (`{ ... }`)
+- Load the theme plugin (using `use()`)
+- Draft the pattern (using `draft()`)
+- Render it to SVG  (using `render()`)
+
+Which can be done as a one-liner since `use()`, `draft()` and
+`render()` are all chainable, as shown below.
+
+## Code example
+
+```js
+import { Aaron } from '@freesewing/aaron' // Design to use
+import { pluginTheme as theme } from '@freesewing/plugin-theme' // SVG theme
+
+const svg = new Aaron( // Instantiate pattern
+  { // Pass in settings. See reference > core > settings
+    sa: 10, // Seam allowance
+    // ...
+    measurements: { // Pass in measurements
+      biceps: 387,
+      chest: 1105,
+      hips: 928,
+      hpsToWaistBack: 502,
+      neck: 420,
+      shoulderSlope: 13,
+      shoulderToShoulder: 481,
+      waistToHips: 139,
+    }
+  })
+  .use(theme) // Load theme plugin
+  .draft() // Draft the pattern
+  .render() // Render to SVG
+
+// svg now holds the generated SVG code
+console.log(svg)
+```
+
+:::note
+
+##### Remarks on the example code
+
+- We are using `@freesewing/aaron` as the design, but you could use any design
+- You probably want to [use your own measurements](/reference/settings/measurements)
+  or you could use [our curated measurements sets](https://freesewing.org/curated-sets) to load measurements.
+- We are using `@freesewing/plugin-theme` to theme our SVG, but you
+  could [pass in your own CSS](/reference/api/svg/style)
+
+:::
+
+## Dependencies
+
+The code above will only work if you've got the required dependencies installed on your system.
+Obviously you need Node.js, but you will also need the following packages:
+
+- `@freesewing/core`: Our core library
+- `@freesewing/plugin-bundle`: Set of common plugins
+- `@freesewing/aaron` or any design you want to use
+- Any design on which the design you choose is built. In this case, Aaron depends on `@freesewing/brian`
+
+For the example above, your `package.json` **dependencies** section will look like this:
+
+```json
+  "dependencies": {
+    "@freesewing/core": "latest"
+    "@freesewing/aaron": "latest",
+    "@freesewing/brian": "latest",
+    "@freesewing/plugin-theme": "latest"
+  }
+```