Multi-host support for PostCodes LogService

Add support for multi-host for all GET and POST method requests under

/redfish/v1/Systems/{computerSystemId}/LogServices/PostCodes/

redfish resource.

Multi-host meson options needed:
-Dexperimental-redfish-multi-computer-system=enabled

Tested:
Redfish-service-validation passes on single-host machine as well as on
yv4 in qemu.

Every postcode entry is displayed in web-ui on single-host and shown
in the curl output when requested on yv4 qemu.

```
curl -w "@curl-format.txt" -c cjar -b cjar -k -X GET
    'https://'"${BMC}"':4443/redfish/v1/Systems/Yosemite_4_Sentinel_Dome_Slot_1_Chassis/LogServices/PostCodes/Entries' \
    -H 'X-Auth-Token: '"$BMCWEB_SESSION_TOKEN"''

{
  "@odata.id": "/redfish/v1/Systems/Yosemite_4_Sentinel_Dome_Slot_1_Chassis/LogServices/PostCodes/Entries",
  "@odata.type": "#LogEntryCollection.LogEntryCollection",
  "Description": "Collection of POST Code Log Entries",
  "Members": [
    {
      "@odata.id": "/redfish/v1/Systems/Yosemite_4_Sentinel_Dome_Slot_1_Chassis/LogServices/PostCodes/Entries/B1-1",
      "@odata.type": "#LogEntry.v1_9_0.LogEntry",
      "Created": "2025-04-22T18:30:51.528798+00:00",
      "EntryType": "Event",
      "Id": "B1-1",
      "Message": "Boot Count: 1; Time Stamp Offset: 0.0000 seconds; POST Code: 0xA1",
      "MessageArgs": [
        "1",
        "0.0000",
        "0xA1"
      ],
      "MessageId": "OpenBMC.0.2.BIOSPOSTCode",
      "Name": "POST Code Log Entry",
      "Severity": "OK"
    },

    ...

    "Members@odata.count": 819,
    "Name": "BIOS POST Code Log Entries"
}

curl -w "@curl-format.txt" -c cjar -b cjar -k -X GET
    'https://'"${BMC}"':4443/redfish/v1/Systems/Yosemite_4_Sentinel_Dome_Slot_1_Chassis/LogServices/PostCodes/Entries/B1-1' \
    -H 'X-Auth-Token: '"$BMCWEB_SESSION_TOKEN"''

{
  "@odata.id": "/redfish/v1/Systems/Yosemite_4_Sentinel_Dome_Slot_1_Chassis/LogServices/PostCodes/Entries/B1-1",
  "@odata.type": "#LogEntry.v1_9_0.LogEntry",
  "Created": "2025-04-22T18:30:51.528798+00:00",
  "EntryType": "Event",
  "Id": "B1-1",
  "Message": "Boot Count: 1; Time Stamp Offset: 0.0000 seconds; POST Code: 0xA1",
  "MessageArgs": [
    "1",
    "0.0000",
    "0xA1"
  ],
  "MessageId": "OpenBMC.0.2.BIOSPOSTCode",
  "Name": "POST Code Log Entry",
  "Severity": "OK"
}
```

POST has been tested on single-host hardware inside web-ui and yv4 qemu
machine with curl. (Postcodes have been copied over to the qemu machine
manually from a single-host machine). No regressions observed.
The postcode dir for the specific host is cleared successfully
on both single- and multi-host machine after the POST.

Change-Id: Ie04cb160a1f2756a04be68e6675a6cecc5f09117
Signed-off-by: Oliver Brewka <oliver.brewka@9elements.com>

Author: mox669

redfish-core/lib/log_services.hpp

@@ -984,7 +984,7 @@ inline void handleSystemsLogServiceCollectionGet(
                     nlohmann::json& logServiceArrayLocal =
                         asyncResp->res.jsonValue["Members"];
                     nlohmann::json::object_t member;
-                    member["@odata.id"] = std::format(
+                    member["@odata.id"] = boost::urls::format(
                         "/redfish/v1/Systems/{}/LogServices/PostCodes",
                         systemName);