Add new setting; reduce fan speed for overhangs.

Not properly tested yet. -- Engine code still under construction.

part of CURA-11966

resources/definitions/fdmprinter.def.json

@@ -4650,6 +4650,19 @@
                         }
                     }
                 },
+                "cool_fan_speed_overhang_factor":
+                {
+                    "label": "Fan Speed Overhang Factor",
+                    "description": "Factor to adjust the fan speed with when overhang walls are printed.",
+                    "unit": "%",
+                    "type": "float",
+                    "minimum_value": "0",
+                    "maximum_value": "200",
+                    "default_value": 100,
+                    "enabled": "cool_fan_enabled",
+                    "settable_per_mesh": false,
+                    "settable_per_extruder": true
+                },
                 "cool_min_layer_time_fan_speed_max":
                 {
                     "label": "Regular/Maximum Fan Speed Threshold",

resources/setting_visibility/advanced.cfg

@@ -98,6 +98,7 @@ cool_min_layer_time
 cool_min_speed
 cool_lift_head
 cool_during_extruder_switch
+cool_fan_speed_overhang_factor
 
 [support]
 support_enable