Add base files and configuration for RGB underglow

app/Kconfig

@@ -138,6 +138,30 @@ config ZMK_ACTION_MOD_TAP
 	
 endmenu
 
+menu "ZMK Lighting"
+
+menuconfig ZMK_RGB_UNDERGLOW
+	bool "RGB Adressable LED Underglow"
+	select LED_STRIP
+
+if ZMK_RGB_UNDERGLOW
+
+config ZMK_RGB_UNDERGLOW_HUE_STEP
+	int "RGB underglow hue step in degrees of 360"
+	default 10
+
+config ZMK_RGB_UNDERGLOW_SAT_STEP
+	int "RGB underglow sturation step in percent"
+	default 10
+
+config ZMK_RGB_UNDERGLOW_BRT_STEP
+	int "RGB underglow brightness step in percent"
+	default 10
+
+endif
+
+endmenu
+
 config HEAP_MEM_POOL_SIZE
 	default 1024