MDL-39802 add cli script for fixing of all deleted users

Use this script if something just set the user.deleted flag instead of calling the delete_user() method.
MDL-39802 fix sloppy user deleting and creating in imsenterprise plugin
MDL-39802 ignore deleted users in category enrolments
MDL-39802 ignore deleted users in cohort enrolments
MDL-39802 ignore deleted users in meta enrolments