PERF: run full vacuum every 90 days (during migration)

Will reclaim space and improve perf

config/locales/server.en.yml

@@ -971,6 +971,8 @@ en:
     enable_cdn_js_debugging: "Allow /logs to display proper errors by adding crossorigin permissions on all js includes."
     show_create_topics_notice: "If the site has fewer than 5 public topics, show a notice asking admins to create some topics."
 
+    vacuum_db_days: "Run VACUUM FULL ANALYZE to reclaim DB space after migrations (set to 0 to disable)"
+
     errors:
       invalid_email: "Invalid email address."
       invalid_username: "There's no user with that username."

config/site_settings.yml

@@ -709,6 +709,11 @@ uncategorized:
   company_short_name: 'Unconfigured Forum'
   company_domain: 'www.example.com'
 
+  vacuum_db_days: 90
+  last_vacuum:
+    default: 0
+    hidden: true
+
   tos_topic_id:
     default: -1
     hidden: true