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/modbus_server/modbus_server.c

@@ -8,7 +8,6 @@
  */
 
 #include <zephyr/device.h>
-#include <zephyr/drivers/misc/vnd7050aj/vnd7050aj.h>
 #include <zephyr/drivers/uart.h>
 #include <zephyr/kernel.h>
 #include <zephyr/logging/log.h>
@@ -20,6 +19,7 @@
 #include <lib/fwu.h>
 #include <lib/modbus_server.h>
 #include <lib/valve.h>
+#include <lib/vnd7050aj.h>
 
 LOG_MODULE_REGISTER(modbus_server, LOG_LEVEL_INF);