[i18n-ar] Translating docs to Arabic

[strikoder]

Hi!

Let's bring the documentation to all the Arabic-speaking community 🌐

Who would want to translate? Please follow the 🤗 TRANSLATING guide. Here is a list of the files ready for translation. Let us know in this issue if you'd like to translate any, and we'll add your name to the list.

Some notes:

• Please translate using an informal tone (imagine you are talking with a friend about transformers 🤗).
• Please translate in a gender-neutral way.
• Add your translations to the folder called <languageCode> inside the source folder.
• Register your translation in <languageCode>/_toctree.yml; please follow the order of the English version.
• Once you're finished, open a pull request and tag this issue by including #issue-number in the description, where issue-number is the number of this issue. Please ping @stevhliu and @MKhalusova for review.
• 🙋 If you'd like others to help you with the translation, you can also post in the 🤗 forums.

Get Started section

• [ ] readme.md
• [ ] index.md
• [ ] quicktour.md
• [ ] installation.md

Tutorial section

• [ ] pipeline_tutorial.md
• [ ] autoclass_tutorial.md
• [ ] preprocessing.md
• [ ] training.md
• [ ] accelerate.md
• [ ] model_sharing.md
• [ ] multilingual.md

[strikoder]

I will start translating the readme.md, then I will move to the tutorial section.