feat: Flat import of markdown repo

This is a flat (without history) import of (some of) the content
from our markdown module.

We've imported this without history because the repo contains our
blog posts and showcases posts content prior to porting them to strapi.

Since this contains many images, it would balloon the size of this repo
to import the full history.

Instead, please refer to the history of the (archived) markdown repo
at: https://github.com/freesewing/markdown

markdown/dev/guides/plugins/loading-run-time-plugins/en.md

@@ -0,0 +1,26 @@
+---
+title: Loading run-time plugins
+order: 40
+---
+
+Run-time plugin are loaded at run time, by passing them to the `use` method of
+an instatiated pattern. That method is chainable, so if you have multiple plugins
+you can just chain them together:
+
+```js
+import Aaron from "@freesewing/aaron";
+import theme from "@freesewing/plugin-theme";
+import i18n from "@freesewing/plugin-i18n";
+
+const myAaron = new Aaron()
+  .use(theme)
+  .use(i18n)
+```
+
+<Tip>
+
+Plugins that use only hooks are typically run-time plugins
+
+</Tip>
+
+