Enhancement: Centralize configuration and automate manifest generation

[wipodev]

Description

This PR improves the developer workflow by centralizing all plugin metadata and automating the generation of the manifest.json file.

The goal is to establish a "Single Source of Truth" within gradle.properties, ensuring that the plugin's metadata remains consistent across the build process, the game manifest, and the development server.

Key Changes

• Centralized Metadata: All Hytale-specific properties (Group, Name, Version, Authors, Main Class, etc.) are now managed in gradle.properties.
• Dynamic Manifest Generation: Replaced the manual updatePluginManifest task with generatePluginManifest. This task creates the manifest.json on the fly inside the build/ directory during the compilation process.
• Cleaner Source Tree: Removed the static manifest.json from src/main/resources to prevent out-of-sync metadata and keep the source folder focused on code and assets.
• Improved runHytale Task: Updated the execution logic to load the plugin from the build resources path, ensuring the server always runs with the latest generated metadata.
• Expanded Manifest Support: Added support for additional fields required for complex plugins, such as Authors, Dependencies, and OptionalDependencies.

Benefits

• Maintainability: Developers only need to edit one file (gradle.properties) to update the entire project.
• Automation: Reduces manual errors when bumping versions or changing the main entry point.
• Standardization: Follows Java/Gradle best practices by keeping generated files out of the source control.