Description

This PR changes the crate structure in a more detailed way.

Checklist

• I opened a draft PR or added the [WIP] to the title if my PR is not ready for review.
• I have reviewed the code by myself.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• I have added tests enough to show how your code behaves and that your code works as expected.

Additional Notes

N/A