Make log messages to clearly identify any Devices.xml issue

[simonyg]

When the devices.xml contains some incomplete DataItem like:

<DataItem type="ANGLE" category="SAMPLE" name="A1actw" subType="ACTUAL" nativeUnits="DEGREE" coordinateSystem="WORK" id="A1actw" />

The agent displays some warning messages:

2026-03-27T15:18:14.935309Z (0x00000900) [warning] MAIN->AgentConfiguration::initialize->AgentConfiguration::loadConfig->Agent::initialize->Agent::loadXMLDeviceFile: Failed to create DataItem: DataItem(): nativeUnits given, but no units for A1actw
2026-03-27T15:18:14.935309Z (0x00000900) [warning] MAIN->AgentConfiguration::initialize->AgentConfiguration::loadConfig->Agent::initialize->Agent::loadXMLDeviceFile: Unexpected element: DataItem
2026-03-27T15:18:14.936250Z (0x00000900) [warning] MAIN->AgentConfiguration::initialize->AgentConfiguration::loadConfig->Agent::initialize->Agent::loadXMLDeviceFile: Error parsing device: DataItem: nativeUnits given, but no units for A1actw
2026-03-27T15:18:14.936250Z (0x00000900) [warning] MAIN->AgentConfiguration::initialize->AgentConfiguration::loadConfig->Agent::initialize->Agent::loadXMLDeviceFile: Error parsing device: DataItems: Invalid element 'DataItem'

and does not include this DataItem A1actw.

The multiple log messages should be consolidated to a single log message like:

line xxx: Error parsing device: DataItem: nativeUnits given, but no units for A1actw. This DataItem is skipped.

[wsobel]

Changed to:

2026-03-27T18:28:25.604603Z (0x00000001faf318c0) [warning] MAIN->AgentConfiguration::initialize->AgentConfiguration::loadConfig->Agent::initialize->Agent::loadXMLDeviceFile: Failed to create DataItem: DataItem(): nativeUnits given, but no units for A1actw
2026-03-27T18:28:25.608333Z (0x00000001faf318c0) [warning] MAIN->AgentConfiguration::initialize->AgentConfiguration::loadConfig->Agent::initialize->Agent::loadXMLDeviceFile: When loading device OKUMA.MachiningCenter, A problem was skipped: DataItem: nativeUnits given, but no units for A1actw
2026-03-27T18:28:25.608372Z (0x00000001faf318c0) [warning] MAIN->AgentConfiguration::initialize->AgentConfiguration::loadConfig->Agent::initialize->Agent::loadXMLDeviceFile: When loading device OKUMA.MachiningCenter, A problem was skipped: DataItems: Invalid element 'DataItem'

The first warning comes from the parser itself, indicating a problem. The last two provide device context. I could soften it some more. The parser doesn't know whether the error will be skipped; it lacks higher-level context indicating whether it is required.