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/reference/plugins/sprinkle/readme.mdx

@@ -0,0 +1,35 @@
+---
+title: plugin-sprinkle
+---
+
+Published as [@freesewing/plugin-sprinkle][1], this plugin provides [the
+sprinkle macro](/reference/macros/sprinkle) which is a faster way to add
+several of the same snippets to your designs (think of it as _sprinkling_ them
+onto your design).
+
+## Installation
+
+```sh
+npm install @freesewing/plugin-sprinkle
+```
+
+## Usage
+
+Either [add it as a part plugins](/reference/api/part/config/plugins) in your
+design, or [add it to a pattern instance with
+Pattern.use()](/reference/api/pattern/use).
+
+To import the plugin for use:
+```js
+import { sprinklePlugin } from '@freesewing/plugin-sprinkle'
+// or
+import { pluginSprinkle } from '@freesewing/plugin-sprinkle'
+```
+
+## Notes
+
+This plugin is part of the [core-plugins bundle](/reference/plugins/core),
+so there is no need to install or import it manually unless you wish to forego
+loading of core plugins yet still want to load this plugin.
+
+[1]: https://www.npmjs.com/package/@freesewing/plugin-sprinkle