add Demo to menu, add weights back

Without weights, the menu is sorted by name.

Author: pdurbin

hugo.yml

@@ -6,14 +6,22 @@ menu:
   main:
     - name: About
       url: /about/
+      weight: 10
     - name: Community
       url: /community/
-    - name: Blog
-      url: /blog/
+      weight: 20
+    - name: Demo
+      url: /#try-the-dataverse-software
+      weight: 30
     - name: Download
       url: /#installing-the-software
+      weight: 40
+    - name: Blog
+      url: /blog/
+      weight: 50
     - name: GitHub
       url: https://github.com/IQSS/dataverse
+      weight: 60
 markup:
   goldmark:
     renderer: