Expose "is_show_location" to control display of event locations
The Event DAO has a boolean field 'is_show_location' that determines whether the event location is shown or not. This field is available via the API and existing code suggests it was intended to be available to event administrators, but it is not currently shown.
This field allows event locations to be configured, but not shown to users. The field already exists and is referenced in multiple places but is not configurable via the GUI.
CRM_Event_Form_ManageEvent_Location::buildQuickForm() adds the field to the form but it is not included in the template - see https://github.com/civicrm/civicrm-core/blob/master/CRM/Event/Form/ManageEvent/Location.php#L184
Add the field to the template templates/CRM/Event/Form/ManageEvent/Location.tpl
This improves consistency between API & GUI.
Original motivation for this was that some events on a client site do not have this field set but there is no way to see or correct this for administrators.