init rgb only once on boot if mod is not present

testing required!!!

applications/services/rgb_backlight/application.fam

@@ -7,4 +7,14 @@ App(
     stack_size=1 * 1024,
     order=95,
     sdk_headers=["rgb_backlight.h"],
-)
+)
+
+App(
+    appid="rgb_backlight_startup",
+    name="RgbBackLightBootSrv",
+    apptype=FlipperAppType.STARTUP,
+    targets=["f7"],
+    entry_point="rgb_backlight_on_system_start",
+    cdefines=["SRV_RGB_BACKLIGHT"],
+    order=270,
+)