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.

lib/README

@@ -0,0 +1,46 @@
+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into the executable file.
+
+The source code of each library should be placed in a separate directory
+("lib/your_library_name/[Code]").
+
+For example, see the structure of the following example libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional. for custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+Example contents of `src/main.c` using Foo and Bar:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+The PlatformIO Library Dependency Finder will find automatically dependent
+libraries by scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html