Improve code organization and restructuring code

[mitsuki31]

What's Changed

• b5f3c88 - Moved all exception classes to a new directory named exception.
• 09f14d6 - Relocated the MatrixUtils class to the core directory.
• 5949e85...944fe65 - Fixed import statements in several classes after the relocation of certain classes.
• d88ffc7 - Removed the public modifier for all methods inside the MatrixUtils interface to avoid confusion.

  In "Java Language Specification" (JLS) 11:

  Every field declaration in the body of an interface is implicitly public, static, and final.
  It is permitted to redundantly specify any or all of these modifiers for such fields.

  Therefore, the access modifier was removed, but the static modifier was retained for code clarity and to avoid confusion.
  For more details, refer to https://docs.oracle.com/javase/specs/jls/se11/html/jls-9.html#jls-9.3.

Summary

In this set of changes, several modifications were made to improve the code organization and clarity of the project. The key changes include:

• The exception classes were moved to a separate directory named exception. This restructuring enhances the project's structure and makes it easier to locate and manage exception-related code.

• The MatrixUtils class was relocated to the core directory. This move ensures that both either utility and core (core classes would be added as feature soon) classes are grouped together, promoting better organization and maintainability.

• Import statements in various classes were fixed after the relocation of certain classes. This ensures that all necessary dependencies are correctly referenced and resolves any compilation errors related to import statements.

• The public modifier was removed for all methods inside the MatrixUtils interface. According to the "Java Language Specification" (JLS) 11, interface fields are implicitly public, static, and final. The removal of the access modifier aligns with this specification, preventing confusion and redundant declaration of access modifiers.

These changes contribute to a more organized and streamlined codebase, improving code clarity, maintainability, and adherence to Java language standards.