Add blank Scratch project for Experience CS

@grega previously added this to production (but not staging) manually.
Since it's useful to have, it feels better to have it a bit more under
source control and to make it available in both staging and production.

Co-authored-by: Seb Jacobs <[email protected]>

Author: floehopper

lib/tasks/projects.rake

@@ -29,6 +29,13 @@ namespace :projects do
         project_type: Project::Types::SCRATCH,
         name: '10 Block Mission',
         user_id: nil
+      },
+      {
+        identifier: 'blank-scratch-starter',
+        locale: 'en',
+        project_type: Project::Types::SCRATCH,
+        name: 'Blank Scratch Starter',
+        user_id: nil
       }
     ]
     projects.each do |attributes|