Add tutorial using Google Colab notebook(s)

[RenkeHuang]

Ideas

• Desired location: https://github.com/RenkeHuang/point_utils/blob/main/tutorials/basic.ipynb, and the corresponding Colab link format will be https://colab.research.google.com/github/RenkeHuang/point_utils/blob/main/tutorials/basic.ipynb
• Use setup_colab.sh script to set up the environment for the Colab notebook:

# Download and run the setup script
!curl -O https://raw.githubusercontent.com/RenkeHuang/point_utils/main/setup_colab.sh
!bash setup_colab.sh

• Add badge to README.md:

# Tutorials
[![Open in Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/RenkeHuang/point_utils/blob/main/tutorials/basic.ipynb)