fix: read a Supermicro X10 with only the OOB license over Redfish (0.3.1)

First run against real hardware over Redfish: an X10DRL-i (BMC 3.91) with
SFT-OOB-LIC. Its Redfish tree is recorded under
tests/fixtures/supermicro-x10drl-i-3.91/redfish, scrubbed.

- A resource refused for want of a further license (403 OemLicenseNotPassed)
  no longer fails the getter. Storage then falls back to SimpleStorage. The
  firmware list falls back to the BMC and BIOS versions when UpdateService
  is withheld.
- get_device_warnings reports bmc_license_partial with the licenses and the
  withheld parts (drives, firmware inventory).
- A placeholder system model ("Super Server") is replaced by the board
  (PartNumber, else the chassis model).

tests/fixtures/supermicro-x10drl-i-3.91/redfish/Managers/1/EthernetInterfaces/index.json

@@ -0,0 +1,13 @@
+{
+ "@odata.context": "/redfish/v1/$metadata#EthernetInterfaceCollection.EthernetInterfaceCollection",
+ "@odata.id": "/redfish/v1/Managers/1/EthernetInterfaces",
+ "@odata.type": "#EthernetInterfaceCollection.EthernetInterfaceCollection",
+ "Description": "Collection of EthernetInterfaces for this Manager",
+ "Members": [
+  {
+   "@odata.id": "/redfish/v1/Managers/1/EthernetInterfaces/1"
+  }
+ ],
+ "Members@odata.count": 1,
+ "Name": "Ethernet Network Interface Collection"
+}