Adjust vars to the coding guidelines
Number element: Use is_numeric in favor of Zend's float validator

The float validator uses Zend_Locale which we have stripped in our vendor library thus leading to erroneous validation.
Further we'll use php-intl instead of Zend_Locale one day :)

fixes #7692
Re-enable auto-refresh
Add new `section` column to icingaweb_user_preference table for pgsql
Dashboard: Use new controller actions

refs #4537
Merge remote-tracking branch 'origin/master' into feature/add-to-dashboard-4537
Dashboard: Remove actions

refs #4537