Add Arabic translation for Open Source Guides

[aseel-aaa]

Hi,
Yes, I’ve read the contributing guidelines
and followed the instructions.

I’ve explained what my changes do: I created/updated the _data/locales/ar.yml file and prepared the _articles/ar/ folder structure. I will start translating the articles after receiving approval to continue.

This PR is an initial setup to:

Get feedback on the translation approach

Ensure everything is structured correctly for Arabic articles

//This work will help Arabic-speaking developers access and learn from the Open Source Guides.

[Ogruj098]

This pull request adds a new article in Arabic, _articles/ar/best-practices.md, which provides comprehensive best practices for open source maintainers. The article covers documentation, communication, handling contributions, leveraging community support, automation, and self-care, offering actionable advice and examples to help maintainers manage their projects more effectively.

New article addition:

• Added _articles/ar/best-practices.md, an in-depth guide for open source maintainers on best practices, including documenting processes, setting expectations, managing contributions, sharing workload, using automation tools, and maintaining personal well-being.

[aseel-aaa]

@Ogruj098 Where's the article ?