📝 TODO: Rearrange ReadMe regarding Environment Setup

[Rexpert]

The current ReadMe is quite complicated, there are various ways to install the dependencies. The ReadMe involves some instructions to build a Virtual Environment with venv, but also some instructions involving Conda setup.

As a Python beginner user, it is better if

1. I can easily install the environment without any hassle
2. I can focus on the virtual environment that I am familiar with instead of using multiple virtual environments.

Expectation:

1. Build a requirements.txt that includes all necessary packages, and write some introductions about how to use it.
2. Rearrange the ReadMe's installation section and add introductions about how to create, activate and deactivate the conda environment.