Arabic: Fix, improve, and update the translation

[agharbeia]

For my contribution to this cool project. I have:

• corrected translation logic in several places, and some ICT-related technical mistranslation in the contribution guidelines
• removed residual from previous editing; repetitions and misplaced words;
• created more fluent wording and phrasing in some places (IMO);
• fixed some typos;
• affected more consistency in wording;
• inserted English names of institutions for reference;
• other minor fixes, including avoiding Latin words qualified by the Arabic article.
• updated the text to the current English: the contribution guide seems to have been based on an earlier source.

[wopian]

Thank you for your contribution 😀