translated README.md to Simplified Chinese

propose Regression french translation readme

Update links for future translated readme

translate 3.1 to Simplified Chinese

Update README.zh-cn.md

add a README.fr.md for Regression base README

propose french translation of Introduction base README

Keep "Machine learning" term in fr translation

Create README.zh-cn.md

Update relative paths

translate README to Simplified Chinese

Propose README.fr.md file for the french translation of introduction base README

Create README.zh.md

translate 2.2 to Simplified Chinese

translate 2.1 to Simplified Chinese

update relative path of translations folder of each lessons and align the title。
更新了各个课程的相对路径，并保持标题翻译的一致性

change relative path to translation folders

2.2

Translate 1.1 and 1.2 to Turkish and fix translation errors in the quiz-app

Add Turkish quiz translation