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/best-practices/en.md

@@ -0,0 +1,20 @@
+---
+title: Design guide
+order: 300
+for: developers
+icons: 
+  - thumbup
+  - pattern
+about: "There's often many different ways to do things. Learn about our conventions and best practices"
+goals:
+ - Re-using measurement and options names
+ - Re-using CSS classes
+ - Respecting draft settings
+ - Using percentage options where possible
+ - Using translation keys for text
+ - Constructing paths counter-clockwise
+---
+
+Here is a list of best practices when designing patterns:
+
+<ReadMore list />