Reverse RDM UID bytes and remove DMX personality

Update struct layout and serialization, and fix UID endianness.

- lib-configstore: Replace the single `personality` byte with `reserved[2]` in DmxNode to preserve layout/padding.
- lib-dmxnode: Remove serialization of the personality field from JSON output (no longer present in the struct).
- lib-rdm: Reverse the order of serial_number bytes when populating uid_[2..5] to correct RDM UID byte ordering.

These changes restore consistency between the in-memory struct and JSON representation and correct the RDM UID construction.

Author: vanvught

lib-configstore/include/configurationstore.h

@@ -167,8 +167,7 @@ struct Flags
 struct DmxNode
 {
     uint32_t flags;
-    uint8_t personality;
-    uint8_t reserved;
+    uint8_t reserved[2];
     uint16_t universe[dmxnode::kParamPorts];
     uint16_t direction;
     uint16_t merge_mode;

lib-dmxnode/src/json/json_config_dmxnode.cpp

@@ -38,7 +38,6 @@ uint32_t GetDmxNode(char* buffer, uint32_t length)
     assert(dmx_node != nullptr);
 
  	return json::helpers::Serialize(buffer, length, [&](JsonDoc& doc) {	
-	    doc[json::DmxNodeParamsConst::kPersonality.name] = "node";
 	    doc[json::DmxNodeParamsConst::kNodeName.name] = dmx_node->GetLongName();
 	    doc[json::DmxNodeParamsConst::kFailsafe.name] = dmxnode::GetFailsafe(dmx_node->GetFailSafe());
 	    doc[json::DmxNodeParamsConst::kDisableMergeTimeout.name] = dmx_node->GetDisableMergeTimeout() ? 1 : 0;

lib-rdm/include/rdm_device_base.h

@@ -65,10 +65,10 @@ class Base
 
         uid_[0] = RDMConst::MANUFACTURER_ID[0];
         uid_[1] = RDMConst::MANUFACTURER_ID[1];
-        uid_[2] = serial_number_[0];
-        uid_[3] = serial_number_[1];
-        uid_[4] = serial_number_[2];
-        uid_[5] = serial_number_[3];
+        uid_[2] = serial_number_[3];
+        uid_[3] = serial_number_[2];
+        uid_[4] = serial_number_[1];
+        uid_[5] = serial_number_[0];
     }
 
     uint8_t uid_[RDM_UID_SIZE];