Fill out "About Yoga", "Laying out a Yoga tree" , and "Styling" (#1591)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1591

Adds initial documentation to these sections.

Reviewed By: joevilches

Differential Revision: D54708141

fbshipit-source-id: b2c1ac20573840833a3e5fde8c7b53f2770cecbd

website-next/docs/styling/display.mdx

@@ -0,0 +1,25 @@
+---
+sidebar_position: 4
+---
+
+import Playground from '@site/src/components/Playground';
+
+# Display
+
+Display controls which layout specification to follow.
+
+**Flex (default)**: The CSS Flexible Box Model specification.
+
+**None**: The node is removed from the layout tree and will not be visible.
+
+<Playground code={`<Layout config={{useWebDefaults: false}}>
+  <Node
+    style={{
+      width: 200,
+      height: 200,
+      padding: 10,
+    }}>
+    <Node style={{margin: 5, height: 50, display: 'flex'}} />
+    <Node style={{margin: 5, height: 50, display: 'none'}} />
+  </Node>
+</Layout>`} />