Fix notebooks helmi

[JMuff22]

• Updated the running on Helmi documentation
• Created the directory content/notebooks/img and moved the image of Helmi into it as well as images for E1 from last year
• Added a note to the students who will be running cirq notebooks that submission is not asynchronous and they may see an error
• Updated E1 notebooks from last year to use the latest qiskit syntax and tested.

This change comes with Docker image version v0.4 deployed to ntoebooks.csc.fi which now runs

git clone https://github.com/ENCCS/qas2023.git $HOME/qas2023
cp -rv $HOME/qas2023/content/notebooks $HOME/

such that notebooks are served in the $HOME directory

[wikfeldt]

thanks a lot! I'll merge and see if the maths will render well