feat ✨: Added .gitignore, README files, partitions, build options, dependencies, and configuration for ESP32-S3 development board using Arduino.

- Added `.gitignore` file to exclude unnecessary build and system files.
- Summary: Added a README file for project headers, improving organization and management of header files in the source codebase.
- Added a README file in the lib directory for project-specific libraries.
- Added new partitions to `partitions.csv`.
- The `git diff` output updates the `platformio.ini` file to include new build and upload options, dependencies, and configuration for an ESP32-S3 development board using Arduino.
- The user has added a new `main.cpp` file, added I2S and FFT functionality to it, and defined a function to calculate the frequency and convert it to a MIDI note number.
- Added a new README file in the `test` directory for PlatformIO Unit Testing.

test/README

@@ -0,0 +1,11 @@
+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html