Docs/update readme (#10)

* docs: update README.md to enhance onboarding and usage guidance

- Revised the README structure to include a Quick Start section for easier onboarding.
- Added detailed installation instructions for Maven and Gradle.
- Expanded the Usage section with comprehensive examples demonstrating result creation, exception handling, and error recovery.
- Introduced new sections on Core Concepts, Implementation Overview, and API Design Philosophy to clarify the operational result pattern.
- Improved documentation for better clarity and consistency across all sections.

* docs: expand Java coding guidelines with modern practices and performance insights

- Enhanced the "Handling No-Things" section to include Java 21 features like pattern matching and sealed classes.
- Added performance comparisons between traditional null checking, Optional usage, and pattern matching.
- Introduced new sections on sorting lists with nulls, using loop labels effectively, and JVM shutdown hooks.
- Updated Java version-specific guidelines to include features from Java 11 and 21, emphasizing best practices for maintainability and robustness.

* Reoved old commands

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Co-authored-by: Jim Mochel <jmochel@landmarkworldwide.com>

Author: jmochel