Add Persian translation for "Getting Started" and update structure (#5)

* update heading levels, structure, and add Getting Started translation

* fix image paths after renaming folder

* Update TOC to include getting_started lecture

Author: Zahra-khanzadeh

lectures/Getting_started.md

@@ -5,7 +5,7 @@ parts:
   numbered: true
   chapters:
   - file: about_py
-  # - file: getting_started
+  - file: Getting_started
   # - file: python_by_example
   # - file: functions
   # - file: python_essentials