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/vnd7050aj/Kconfig

@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: Apache-2.0
+
+config VND7050AJ
+	bool "VND7050AJ driver"
+	default n
+	select ADC
+	select GPIO
+	help
+	    Enable support for the VND7050AJ high-side driver.
+
+if VND7050AJ
+    config VND7050AJ_INIT_PRIORITY
+        int "VND7050AJ initialization priority"
+        default 80
+        help
+            VND7050AJ driver initialization priority. This should be set to a value
+            that ensures the driver is initialized after the required subsystems
+            (like GPIO, ADC) but before application code runs.
+
+    config VND7050AJ_LOG_LEVEL
+        int "VND7050AJ Log level"
+        depends on LOG
+        default 3
+        range 0 4
+        help
+            Sets log level for VND7050AJ driver.
+            Levels are:
+            0 OFF, do not write
+            1 ERROR, only write LOG_ERR
+            2 WARNING, write LOG_WRN in addition to previous level
+            3 INFO, write LOG_INF in addition to previous levels
+            4 DEBUG, write LOG_DBG in addition to previous levels
+endif # VND7050AJ