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/svgattr/readme.mdx

@@ -0,0 +1,51 @@
+---
+title: plugin-svgattr
+---
+
+Published as [@freesewing/plugin-svgattr][1], this plugin takes an object of
+key-value pairs and adds them as attributes of the `<svg>` tag
+of a pattern's SVG document on render.
+
+## Installation
+
+```sh
+npm install @freesewing/plugin-svgattr
+```
+
+## 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 { svgAttrPlugin } from '@freesewing/plugin-svgattr'
+// or
+import { svgattrPlugin } from '@freesewing/plugin-svgattr'
+// or
+import { pluginSvgAttr } from '@freesewing/plugin-svgattr'
+// or
+import { pluginSvgattr } from '@freesewing/plugin-svgattr'
+```
+:::tip
+For convenience, this plugin is exported
+under multiple names with variations of capitalization.
+:::
+
+## Notes
+
+To provide the attributes for the `<svg>` tag, you will need to pass a
+second argument which holds key-value pairs.
+It should be an `Object` structured as such:
+
+```js
+{
+  key1: 'value1',
+  key2: 'value2',
+  key3: 'value3',
+  // More key-value pairs can follow...
+}
+```
+
+[1]: https://www.npmjs.com/package/@freesewing/plugin-svgattr