Add DMTF mockup fixtures and test helpers

Unmodified files from DMTF Redfish-Publications (public-rackmount1, public-localstorage, public-telemetry), only those the tests use, each set with DMTF's BSD-3-Clause license and a COMMANDS.txt naming the source commit and request paths.

conftest.py loads them by request path and serves a mockup over mocked HTTP, with a SessionService that hands out a token, for the transport tests.

tests/fixtures/dmtf-public-localstorage/Chassis/1U/Drives/32ADF365C6C1B7BD/index.json

@@ -0,0 +1,40 @@
+{
+    "@odata.type": "#Drive.v1_22_0.Drive",
+    "Id": "32ADF365C6C1B7BD",
+    "Name": "Drive Sample",
+    "IndicatorLED": "Lit",
+    "Model": "C123",
+    "Revision": "100A",
+    "Status": {
+        "State": "Enabled",
+        "Health": "OK"
+    },
+    "CapacityBytes": 899527000064,
+    "FailurePredicted": false,
+    "Protocol": "SAS",
+    "MediaType": "HDD",
+    "Manufacturer": "Contoso",
+    "SerialNumber": "1234570",
+    "PartNumber": "C123-1111",
+    "Identifiers": [
+        {
+            "DurableNameFormat": "NAA",
+            "DurableName": "32ADF365C6C1B7BD"
+        }
+    ],
+    "HotspareType": "Global",
+    "HotspareReplacementMode": "Revertible",
+    "EncryptionAbility": "SelfEncryptingDrive",
+    "EncryptionStatus": "Unlocked",
+    "RotationSpeedRPM": 15000,
+    "BlockSizeBytes": 512,
+    "CapableSpeedGbs": 12,
+    "NegotiatedSpeedGbs": 12,
+    "Actions": {
+        "#Drive.SecureErase": {
+            "target": "/redfish/v1/Chassis/1U/Drives/32ADF365C6C1B7BD/Actions/Drive.SecureErase"
+        }
+    },
+    "@odata.id": "/redfish/v1/Chassis/1U/Drives/32ADF365C6C1B7BD",
+    "@Redfish.Copyright": "Copyright 2014-2026 DMTF. For the full DMTF copyright policy, see http://www.dmtf.org/about/policies/copyright."
+}