Added Fortigate FG-120G, and created front/rear images (#1991)

device-types/Fortinet/FG-120G.yaml

@@ -0,0 +1,83 @@
+---
+manufacturer: Fortinet
+model: FortiGate 120G
+slug: fortinet-fg-120g
+part_number: FG-120G
+u_height: 1
+is_full_depth: false
+airflow: side-to-rear
+comments: '[FortiGate 120G Series Datasheet](https://www.fortinet.com/content/dam/fortinet/assets/data-sheets/fortigate-120g-series.pdf)'
+console-ports:
+  - name: Console
+    type: rj-45
+power-ports:
+  - name: PS1
+    type: iec-60320-c14
+    maximum_draw: 40
+    allocated_draw: 38
+  - name: PS2
+    type: iec-60320-c14
+    maximum_draw: 40
+    allocated_draw: 38
+interfaces:
+  - name: ha
+    type: 1000base-t
+  - name: mgmt
+    type: 1000base-t
+    mgmt_only: true
+  - name: port1
+    type: 1000base-t
+  - name: port2
+    type: 1000base-t
+  - name: port3
+    type: 1000base-t
+  - name: port4
+    type: 1000base-t
+  - name: port5
+    type: 1000base-t
+  - name: port6
+    type: 1000base-t
+  - name: port7
+    type: 1000base-t
+  - name: port8
+    type: 1000base-t
+  - name: port9
+    type: 1000base-t
+  - name: port10
+    type: 1000base-t
+  - name: port11
+    type: 1000base-t
+  - name: port12
+    type: 1000base-t
+  - name: port13
+    type: 1000base-t
+  - name: port14
+    type: 1000base-t
+  - name: port15
+    type: 1000base-t
+  - name: port16
+    type: 1000base-t
+  - name: x1
+    type: 10gbase-x-sfpp
+  - name: x2
+    type: 10gbase-x-sfpp
+  - name: x3
+    type: 10gbase-x-sfpp
+  - name: x4
+    type: 10gbase-x-sfpp
+  - name: port17
+    type: 1000base-x-sfp
+  - name: port18
+    type: 1000base-x-sfp
+  - name: port19
+    type: 1000base-x-sfp
+  - name: port20
+    type: 1000base-x-sfp
+  - name: port21
+    type: 1000base-x-sfp
+  - name: port22
+    type: 1000base-x-sfp
+  - name: port23
+    type: 1000base-x-sfp
+  - name: port24
+    type: 1000base-x-sfp