feat: Add various content types to docusaurus (#7231)

This brings blog posts, showcase posts, and newsletter editions into the Docusaurus site.

It also adds support for using TailwindCSS inside a container. So this will probably end up being the new freesewing.org site in v4.

sites/dev/docs/tutorials/pattern-design/part2/fitting-the-neck-opening/readme.mdx

@@ -1,10 +1,10 @@
 ---
 title: Fitting the neck opening
-order: 70
+sidebar_position: 70
 ---
 
 We are not going to create some opening that we _hope_ is the right size, we're
-going to make sure it is.  Here's how we'll make sure the neck opening is _just
+going to make sure it is. Here's how we'll make sure the neck opening is _just
 right_:
 
 <Example tutorial caption="It might look the same as before, but now it's just right">
@@ -19,54 +19,56 @@ function draftBib({
   part,
 }) {
 
-  /*
-   * Construct the quarter neck opening
-   */
-// highlight-start
+/\*
+
+- Construct the quarter neck opening
+  _/
+  // highlight-start
   let tweak = 1
-  let target = (measurements.head * options.neckRatio) /4
+  let target = (measurements.head _ options.neckRatio) /4
   let delta
   do {
-// highlight-end
-    points.right = new Point(
-// highlight-start
-      tweak * measurements.head / 10, 
-// highlight-end
-      0
-    )
-    points.bottom = new Point(
-      0, 
-// highlight-start
-      tweak * measurements.head / 12
-// highlight-end
-    )
+  // highlight-end
+  points.right = new Point(
+  // highlight-start
+  tweak _ measurements.head / 10,
+  // highlight-end
+  0
+  )
+  points.bottom = new Point(
+  0,
+  // highlight-start
+  tweak _ measurements.head / 12
+  // highlight-end
+  )
+
 
     points.rightCp1 = points.right.shift(
-      90, 
+      90,
       points.bottom.dy(points.right) / 2
     )
     points.bottomCp2 = points.bottom.shift(
-      0, 
+      0,
       points.bottom.dx(points.right) / 2
     )
 
     paths.quarterNeck = new Path()
       .move(points.right)
       .curve(
-        points.rightCp1, 
-        points.bottomCp2, 
+        points.rightCp1,
+        points.bottomCp2,
         points.bottom
       )
 
-
 // highlight-start
-    delta = paths.quarterNeck.length() - target
-    if (delta > 0) tweak = tweak * 0.99
-    else tweak = tweak * 1.02
-  } while (Math.abs(delta) > 1)
+delta = paths.quarterNeck.length() - target
+if (delta > 0) tweak = tweak _ 0.99
+else tweak = tweak _ 1.02
+} while (Math.abs(delta) > 1)
 // highlight-end
-  return part
+return part
 }
+
 ```
 </Example>
 
@@ -94,3 +96,4 @@ are within 1 mm of our target value.
 
 Now that we're happy with the length of our quarter neck opening, let's
 complete the entire neck opening.
+```