feat: Integrate VND7050AJ driver and enhance gateway settings

This commit introduces the VND7050AJ driver as a new submodule and integrates it into the project.

Key changes include:
- Added  as a git submodule.
- Enhanced the gateway application () with LittleFS and the settings subsystem.
  - Implemented new shell commands (, , ) for managing custom settings.
  - Added functionality to compact the settings file.
- Updated  to include new library dependencies and log  return code.
- Adjusted include paths for  in relevant files.
Signed-off-by: Eduard Iten <eduard@iten.pro>

software/lib/shell_modbus/shell_modbus.c

@@ -10,6 +10,7 @@
 
 #include <zephyr/shell/shell.h>
 #include <lib/modbus_server.h>
+#include <stdio.h>
 #include <stdlib.h>
 
 /**