Enhance project setup with Docker, CI/CD, and contributor guidelines

[devops2626]

Summary

This pull request enhances the project setup by introducing containerization support, automated CI/CD workflows, developer environment configurations, and comprehensive contribution guidelines.

Key Changes

• Docker Support: Added a multi-stage Dockerfile along with a .dockerignore file to optimize container image sizes and build times.
• Development Environment: Added VS Code Dev Container configuration (.devcontainer) to provide a consistent, pre-configured development environment.
• CI/CD Workflows: Integrated GitHub Actions pipelines for automated testing, linting, and multi-platform build checks.
• Documentation & Guidelines: Included a detailed CONTRIBUTING.md guide along with updated project templates and documentation.
• Fixes & Maintenance: Resolved land_cover import and module conflicts, merged upstream updates, and updated dependabot.yml.

How to Test

1. Container Build: Run docker build -t arnis . to verify the multi-stage build completes successfully.
2. Dev Container: Reopen the workspace inside VS Code using the Dev Containers extension.
3. CI/CD: Verify that GitHub Actions workflows execute and pass successfully.