Update X20.yaml with positions (#84)

device-types/Appear/X20.yaml

@@ -10,18 +10,32 @@ comments: The Appear X10/X20 Platform is a dedicated solution for high speed vid
 front_image: true
 module-bays:
   - name: Control Slot 1
+    position: '1'
   - name: Control Slot 2
+    position: '2'
   - name: PSU Slot 1
   - name: PSU Slot 2
   - name: Slot 3
+    position: '3'
   - name: Slot 4
+    position: '4'
   - name: Slot 5
+    position: '5'
   - name: Slot 6
+    position: '6'
   - name: Slot 7
+    position: '7'
   - name: Slot 8
+    position: '8'
   - name: Slot 9
+    position: '9'
   - name: Slot 10
+    position: '10'
   - name: Slot 11
+    position: '11'
   - name: Slot 12
+    position: '12'
   - name: Slot 13
+    position: '13'
   - name: Slot 14
+    position: '14'