ESP32 Tensorflow micro speech with the external microphone

This tutorial covers how to use Tensorflow micro speech with ESP32 with an external microphone I2S. In other words, we want to customize the Tensorflow micro speech example so that it runs on an ESP32 connected to an external microphone using the I2S protocol. In this example, we will use the INMP441 connected to the ESP32 to capture the audio. While the ESP32-EYE has a built-in microphone, if we want to use the Tensorflow micro speech with the ESP32 we need an external microphone that supports the I2S. Moreover, in this tutorial, we will use a custom model so that the ESP32 with INMP441 can recognize not only the yes or no words but other words too.