asw-v01: archive deferred content (packs, site, lab, legacy examples)

- 2.1: packs/ -> archive/packs/
- 2.2: site/ -> archive/site/
- 2.3: src/lab/ -> archive/lab/
- 2.4: examples/ -> archive/examples-legacy/ (SSI-based)

archive/site/data/nav.yml

@@ -0,0 +1,13 @@
+items:
+  - name: Docs
+    url: /docs/
+    weight: 1
+  - name: Layouts
+    url: /layouts/
+    weight: 2
+  - name: Packs
+    url: /docs/packs/overview/
+    weight: 3
+  - name: Lab
+    url: /lab/
+    weight: 4