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/tutorials/getting-started-mac/installing-nvm/readme.mdx

@@ -0,0 +1,33 @@
+---
+title: Installing nvm
+order: 15
+---
+
+FreeSewing is built with [Node.js](https://nodejs.org/), a JavaScript runtime.
+
+You'll need to install Node.js on your system, and to do so, we'll
+use [`nvm`](https://github.com/nvm-sh/nvm), short for _Node Version Manager_.
+
+Using `nvm` has a number of benefits in comparison with installing Node.js from
+the Node.js website, or from a package that came with macOS.
+
+- You can easily switch between different Node.js versions
+- Everything gets installed in your home folder, avoiding permission problems
+
+To setup `nvm`, [follow the install instructions in the nvm
+README](https://github.com/nvm-sh/nvm#installing-and-updating).
+
+After the installation, try running the following command:
+
+```bash
+nvm
+```
+
+If all goes well, it should show you the `nvm` help.
+
+:::tip
+
+If you get `nvm: command not found` or something similar, close the current terminal
+window, and open a new one. Now `nvm` should be found.
+
+:::