Translate ancient machine_head_shape settings

It has been machine_head_polygon for a while.

Contributes to issue CURA-1278.

resources/definitions/grr_neo.def.json

@@ -35,17 +35,13 @@
         "machine_nozzle_cool_down_speed": {
             "default_value": 2
         },
-        "machine_head_shape_min_x": {
-            "default_value": 75
-        },
-        "machine_head_shape_min_y": {
-            "default_value": 18
-        },
-        "machine_head_shape_max_x": {
-            "default_value": 18
-        },
-        "machine_head_shape_max_y": {
-            "default_value": 35
+        "machine_head_polygon": {
+            "default_value": [
+                [-75, -18],
+                [-75, 35],
+                [18, 35],
+                [18, -18]
+            ]
         },
         "machine_nozzle_gantry_distance": {
             "default_value": 55

resources/definitions/innovo_inventor.def.json

@@ -32,17 +32,13 @@
         "machine_nozzle_size": {
             "default_value": 0.4
         },
-        "machine_head_shape_min_x": {
-            "default_value": 43.7
-        },
-        "machine_head_shape_min_y": {
-            "default_value": 19.2
-        },
-        "machine_head_shape_max_x": {
-            "default_value": 43.7
-        },
-        "machine_head_shape_max_y": {
-            "default_value": 55
+        "machine_head_polygon": {
+            "default_value": [
+                [-43.7, -19.2],
+                [-43.7, 55],
+                [43.7, 55],
+                [43.7, -19.2]
+            ]
         },
         "machine_nozzle_gantry_distance": {
             "default_value": 82.3

resources/definitions/maker_starter.def.json

@@ -37,18 +37,6 @@
         "machine_nozzle_cool_down_speed": {
             "default_value": 2
         },
-        "machine_head_shape_min_x": {
-            "default_value": 0
-        },
-        "machine_head_shape_min_y": {
-            "default_value": 0
-        },
-        "machine_head_shape_max_x": {
-            "default_value": 0
-        },
-        "machine_head_shape_max_y": {
-            "default_value": 0
-        },
         "machine_nozzle_gantry_distance": {
             "default_value": 55
         },

resources/definitions/prusa_i3.def.json

@@ -41,17 +41,13 @@
         "machine_nozzle_cool_down_speed": {
             "default_value": 2
         },
-        "machine_head_shape_min_x": {
-            "default_value": 75
-        },
-        "machine_head_shape_min_y": {
-            "default_value": 18
-        },
-        "machine_head_shape_max_x": {
-            "default_value": 18
-        },
-        "machine_head_shape_max_y": {
-            "default_value": 35
+        "machine_head_polygon": {
+            "default_value": [
+                [-75, -18],
+                [-75, 35],
+                [18, 35],
+                [18, -18]
+            ]
         },
         "machine_nozzle_gantry_distance": {
             "default_value": 55

resources/definitions/prusa_i3_xl.def.json

@@ -41,17 +41,13 @@
         "machine_nozzle_cool_down_speed": {
             "default_value": 2.0
         },
-        "machine_head_shape_min_x": {
-            "default_value": 75
-        },
-        "machine_head_shape_min_y": {
-            "default_value": 18
-        },
-        "machine_head_shape_max_x": {
-            "default_value": 18
-        },
-        "machine_head_shape_max_y": {
-            "default_value": 35
+        "machine_head_polygon": {
+            "default_value": [
+                [-75, -18],
+                [-75, 35],
+                [18, 35],
+                [18, -18]
+            ]
         },
         "machine_nozzle_gantry_distance": {
             "default_value": 55

resources/definitions/rigidbot.def.json

@@ -31,18 +31,6 @@
         "machine_nozzle_cool_down_speed": {
             "default_value": 2
         },
-        "machine_head_shape_min_x": {
-            "default_value": 0
-        },
-        "machine_head_shape_min_y": {
-            "default_value": 0
-        },
-        "machine_head_shape_max_x": {
-            "default_value": 0
-        },
-        "machine_head_shape_max_y": {
-            "default_value": 0
-        },
         "machine_nozzle_gantry_distance": {
             "default_value": 0
         },

resources/definitions/rigidbot_big.def.json

@@ -34,18 +34,6 @@
         "machine_nozzle_cool_down_speed": {
             "default_value": 2
         },
-        "machine_head_shape_min_x": {
-            "default_value": 0
-        },
-        "machine_head_shape_min_y": {
-            "default_value": 0
-        },
-        "machine_head_shape_max_x": {
-            "default_value": 0
-        },
-        "machine_head_shape_max_y": {
-            "default_value": 0
-        },
         "machine_nozzle_gantry_distance": {
             "default_value": 0
         },