ESP32 DAC output documentation (#617)

* Add documentation for ESP32 DAC output

* Fix SEO

* Update images/dac.svg

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

components/output/esp32_dac.rst

@@ -0,0 +1,46 @@
+ESP32 DAC
+=========
+
+.. seo::
+    :description: Instructions for setting up ESP32 digital-to-analog converter.
+    :image: dac.svg
+
+The ESP32 DAC platform allows you to output arbitrary voltages using the 8-bit DAC on the ESP32. Two pins are supported: GPIO25 (Channel 1) and GPIO26 (Channel 2).
+
+The output level is a percentage of VCC (3.3V).
+
+
+.. code-block:: yaml
+
+    # Example configuration entry
+    output:
+      - platform: esp32_dac
+        pin: GPIO25
+        id: dac_output
+
+    # Example usage
+    on_...:
+      then:
+        - output.set_level:
+            id: dac_output
+            level: 50%
+
+
+Configuration variables:
+------------------------
+
+- **pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin to use DAC on. Only GPIO25 and GPIO26 are supported.
+- **id** (**Required**, :ref:`config-id`): The id to use for this output component.
+- All other options from :ref:`Output <config-output>`.
+
+See Also
+--------
+
+- :doc:`/components/output/index`
+- :doc:`/components/output/ledc`
+- :doc:`/components/output/esp8266_pwm`
+- :doc:`/components/light/monochromatic`
+- :doc:`/components/fan/speed`
+- :doc:`/components/power_supply`
+- :apiref:`esp32_dac/esp32_dac.h`
+- :ghedit:`Edit`

images/dac.svg

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+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M20 4H4c-1.1 0-2 .9-2 2v12c0 1.1.9 2 2 2h16c1.1 0 2-.9 2-2V6c0-1.1-.9-2-2-2z"/><path d="M3.7 8.8h1.8c1.9 0 3.1 1 3.1 3.2s-1.2 3.3-3 3.3H3.7V8.8zm1.7 5.4c1 0 1.7-.5 1.7-2.1s-.7-2-1.7-2h-.2v4.1h.2zm5.7-5.4h1.8l2 6.5h-1.6l-.8-3.3c-.2-.7-.4-1.4-.5-2.1-.2.7-.3 1.5-.5 2.1l-.8 3.3H9.1l2-6.5zm-.7 3.9h3.1v1.1h-3.1v-1.1zm5.1-.6c0-2.2 1.4-3.4 3.1-3.4.8 0 1.5.4 1.9.8l-.8.9c-.3-.3-.7-.5-1.1-.5-.9 0-1.6.8-1.6 2.1s.7 2.1 1.7 2.1c.5 0 .9-.2 1.2-.6l.8.9c-.5.6-1.3 1-2.1 1-1.7.1-3.1-1.1-3.1-3.3z" fill="#fff"/></svg>

index.rst

@@ -199,6 +199,7 @@ Output Components
     ESP8266 Software PWM, components/output/esp8266_pwm, pwm.png
     Slow PWM, components/output/slow_pwm, pwm.png
     GPIO Output, components/output/gpio, pin.svg
+    ESP32 DAC, components/output/esp32_dac, dac.svg
     ESP32 LEDC, components/output/ledc, pwm.png
     AC Dimmer, components/output/ac_dimmer, ac_dimmer.svg
     PCA9685, components/output/pca9685, pca9685.jpg