[Core] Change OLED task function to be boolean (#14864)

* [Core] Add kb level callbacks to OLED driver

* Update keyboards and keymaps

* Update docs

* Update userspace configs

* Add fix for my keymap ...

* update lefty

keyboards/0xcb/1337/keymaps/via/keymap.c

@@ -168,7 +168,7 @@ static void render_rgbled_status(void) {
         oled_write_ln_P(PSTR("\n"), false);
     }
 }
-void oled_task_user(void) {
+bool oled_task_user(void) {
     static bool finished_timer = false;
     if (!finished_timer && (timer_elapsed(startup_timer) < 1000)) {
         render_logo();
@@ -181,5 +181,6 @@ void oled_task_user(void) {
         render_rgbled_status();
         render_logo_font();
     }
+    return false;
 }
 #endif