Use the grading client for setting package environment

[HuangJunye]

The package already have the proper setup of requirements-qiskit.txt and in setup.py. We should put this installation code inside challenges notebooks.

pip install 'qc-grader[qiskit,jupyter] @ git+https://github.com/qiskit-community/Quantum-Challenge-Grader.git'

There is nothing to change in this repo itself. Opening this issue to remind ourselves for the next coding challenges event.