Add mockup files for the driver tests

UpdateService, the system's EthernetInterfaces and all chassis Sensors from public-rackmount1, unmodified.

tests/fixtures/dmtf-public-rackmount1/Chassis/1U/Sensors/AmbientTemp/index.json

@@ -0,0 +1,16 @@
+{
+    "@odata.type": "#Sensor.v1_14_0.Sensor",
+    "Id": "AmbientTemp",
+    "Name": "Ambient Temperature",
+    "PhysicalContext": "Room",
+    "Status": {
+        "State": "Enabled",
+        "Health": "OK"
+    },
+    "Reading": 22.5,
+    "ReadingUnits": "Cel",
+    "ReadingRangeMin": 0,
+    "ReadingRangeMax": 75,
+    "@odata.id": "/redfish/v1/Chassis/1U/Sensors/AmbientTemp",
+    "@Redfish.Copyright": "Copyright 2014-2026 DMTF. For the full DMTF copyright policy, see http://www.dmtf.org/about/policies/copyright."
+}