Import "Override CiviCRM Settings" wiki page

Created by: seancolsen

This wiki page: https://wiki.civicrm.org/confluence/display/CRMDOC/Override+CiviCRM+Settings

is referenced here: https://docs.civicrm.org/dev/en/latest/framework/setting/#what-is-a-setting

would be good to bring in that content (or remove the link, if the content is not useful).