Disable dashboard email deliveries

We have to doble check all emails deliveries from the dashboard.

Using a setting to skip all dashboard email deliveries for now.

Note that a rake task to activated the `Setting["dashboard.emails"]` will need to be addded when we want to activate deliveries of these emails.

db/seeds.rb

@@ -139,5 +139,8 @@ Setting["proposals.email_description"] = nil
 Setting["proposals.poster_short_title"] = nil
 Setting["proposals.poster_description"] = nil
 
+# Dashboard
+Setting["dashboard.emails"] = nil
+
 # Default custom pages
 load Rails.root.join("db", "pages.rb")