add Curtis Agha to the list of contributors

docs: translate lesson 4 to Japanese

updated Turkish readme.md file table of contents

updated Spanish table of contents to point to Spanish lessons

updated the table of contents for the Italian translation

converted images in the Hindi lessons to mermaid format

updaed images in the Chinese lessons to mermaid format

updated lesson 4 in Russian to include mermaid images

A partial update to the IT lesson 4 to mermaid format

updated the Mongolian images to mermaid format

translated lesson 13 into Spanish

translated lesson 12 into Spanish

translated lesson 11 into Spanish

updated Mongolian filenames

updated lesson 4 in Turkish with mermaid diagrams