Update guidelines, enhance ItemBuilder, and add 1.21.5 support

Expanded coding guidelines to enforce consistent Lombok usage and improve null safety. Enhanced ItemBuilder with advanced customization, better documentation, and parameter validation. Updated dependencies and compatibility for Minecraft 1.21.5.

Update SimpleMenu to support abstract methods and improve title handling

Refactored `SimpleMenu` to be an abstract class, ensuring `onSetItems` must be implemented by subclasses. Introduced overloaded constructors to handle both `String` and `Component` titles, integrating `TextBuilder` for string colorization. Adjusted `pom.xml` to update project version and moved `finalName` from plugin configuration to build settings.

Update signing plugin executions in Maven build lifecycle

Renamed the verify phase execution ID and added a new execution for the package phase to ensure artifacts are signed at both stages. This improves clarity and ensures consistent signing behavior during the build process.

Refactor POM and update documentation structure.

Expanded the POM with project metadata, licensing, and additional plugins for sources, Javadocs, and artifact signing. Revised documentation to streamline core component references and improve developer usability.

Refactor javadoc comments for clarity and consistency

Enhanced javadoc comments across multiple classes for improved readability and consistency, while maintaining semantic context. Adjusted descriptions to ensure clarity in method purposes, parameter meanings, and return values. This improves maintainability and developer experience when working with the codebase.

Refactor javadoc comments for clarity and consistency

Enhanced javadoc comments across multiple classes for improved readability and consistency, while maintaining semantic context. Adjusted descriptions to ensure clarity in method purposes, parameter meanings, and return values. This improves maintainability and developer experience when working with the codebase.

Update logging system and bump version to 2.2.1

This release refactors the logging system, replacing direct calls with a queued system for better scalability and asynchronous handling using coroutines. Updated plugin lifecycle behavior to align with the new logging approach. Incremented version to 2.2.1 and updated references in build files.

Add release notes for version 2.2.0 and update README

Introduced `RELEASE_NOTES.md` outlining new features, including enhanced data persistence, security improvements, and Java 21 compatibility. Updated `README.md` to reflect updated features and installation instructions for NDCore 2.2.0.

Add missing newlines and clean up unused imports

Inserted newlines for better readability and code organization across multiple files. Additionally, removed unused imports to improve code clarity and maintainability.

Upgrade to NDCore v2.0.0 with major refactoring and new features

Removed outdated files, introduced player economy management, and added freeze/unfreeze event handling. Improved plugin structure by refining configuration and coroutine management while ensuring backward compatibility.