add lab1 and lec 4 worksheet

sum23/labs/lab1/README.md

sum23/labs/lab1/double.py

sum23/labs/lab1/hello.py

sum23/labs/lab1/images/README.md

sum23/labs/lab1/images/finder_preferences.png

sum23/labs/lab1/images/finder_preferences_settings.png

sum23/labs/lab1/images/github.png

sum23/labs/lab1/images/html_error.jpg

sum23/labs/lab1/images/jupyter.jpg

sum23/labs/lab1/images/jupyter_lab.jpg

sum23/labs/lab1/images/mac-documents.png

sum23/labs/lab1/images/new_tab.jpg

sum23/labs/lab1/images/raw.png

sum23/labs/lab1/images/raw_gitlab.png

sum23/labs/lab1/images/raw_gitlab_button.png

sum23/labs/lab1/images/save.png

sum23/labs/lab1/images/save_mac.png

sum23/labs/lab1/images/save_windows.png

sum23/labs/lab1/images/windows-documents.png

sum23/labs/lab1/images/windows_file_ext.png