samples: Add blinky tone

- Use `tone` and `noTone` functions to blink led at 1hz with duty cycle
  50% on any digital pin

Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>

samples/blinky_tone/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+cmake_path(SET ZephyrBase $ENV{ZEPHYR_BASE})
+set(DTC_OVERLAY_FILE ${ZephyrBase}/../modules/lib/Arduino-Zephyr-API/variants/${BOARD}/${BOARD}.overlay)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(blinky)
+
+target_sources(app PRIVATE src/main.cpp)
+
+zephyr_compile_options(-Wno-unused-variable -Wno-comment)

samples/blinky_tone/README.rst

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+.. _blinky-tone-sample:
+
+Blinky Tone
+############
+
+Overview
+********
+
+This Arduino Blinky sample blinks an LED forever using the `tone` and `noTone`.
+
+Requirements
+************
+
+Your board must:
+
+#. Have an LED connected via a GPIO pin (these are called "User LEDs" on many of
+   Zephyr's :ref:`boards`).
+#. Have the LED configured using the ``led0`` devicetree alias.
+
+Building and Running
+********************
+
+Build and flash Blinky as follows,
+
+```sh
+$> west build  -p -b arduino_nano_33_ble samples/basic/blinky_tone/ -DZEPHYR_EXTRA_MODULES=/home/$USER/zephyrproject/modules/lib/Arduino-Core-Zephyr
+
+$> west flash --bossac=/home/$USER/.arduino15/packages/arduino/tools/bossac/1.9.1-arduino2/bossac
+```
+
+After flashing, the LED starts to blink. If a runtime error occurs, the sample
+exits without printing to the console.
+
+Adding board support
+********************
+
+To add support for your board, add something like this to your devicetree:
+
+.. code-block:: DTS
+
+   / {
+   	aliases {
+   		led0 = &myled0;
+   	};
+
+   	leds {
+   		compatible = "gpio-leds";
+   		myled0: led_0 {
+   			gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;
+                };
+   	};
+   };
+
+The above sets your board's ``led0`` alias to use pin 13 on GPIO controller
+``gpio0``. The pin flags :c:macro:`GPIO_ACTIVE_HIGH` mean the LED is on when
+the pin is set to its high state, and off when the pin is in its low state.
+
+Tips:
+
+- See :dtcompatible:`gpio-leds` for more information on defining GPIO-based LEDs
+  in devicetree.
+
+- If you're not sure what to do, check the devicetrees for supported boards which
+  use the same SoC as your target. See :ref:`get-devicetree-outputs` for details.
+
+- See :zephyr_file:`include/zephyr/dt-bindings/gpio/gpio.h` for the flags you can use
+  in devicetree.
+
+- If the LED is built in to your board hardware, the alias should be defined in
+  your :ref:`BOARD.dts file <devicetree-in-out-files>`. Otherwise, you can
+  define one in a :ref:`devicetree overlay <set-devicetree-overlays>`.

samples/blinky_tone/prj.conf

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+CONFIG_GPIO=y
+CONFIG_CPLUSPLUS=y
+CONFIG_ARDUINO_API=y

samples/blinky_tone/src/main.cpp

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* Blink inbuilt LED with tone */
+
+#include <Arduino.h>
+
+void setup() { 
+	pinMode(LED_BUILTIN, OUTPUT); 
+}
+
+void loop() {
+	tone(LED_BUILTIN, 1, 10000);
+	delay(15000);
+	tone(LED_BUILTIN, 1);
+	delay(10000);
+	noTone(LED_BUILTIN);
+	delay(5000);
+}