Docs should be clear that the example notebooks aren't standalone

[billti]

The quickstart docs state "You can also view a related code sample in a Jupyter notebook format, along with several other examples, in the examples folder of the GitHub repository".

I downloaded the extended_hubbard.ipynb notebook from there, and the sample data file it referenced, but it still took me a while to troubleshoot why I was getting the below.

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
Cell In[4], [line 1](vscode-notebook-cell:?execution_count=4&line=1)
----> [1](vscode-notebook-cell:?execution_count=4&line=1) from utils.viz_utils import generate_cube_data_with_info
      2 
      3 # Identify orbitals from HOMO-2 to LUMO+2
      4 hf_orbitals = wfn_hf.get_orbitals()

ModuleNotFoundError: No module named 'utils'

After some digging I realized the notebooks are not standalone and depend on modules in the sibling https://github.com/microsoft/qdk-chemistry/tree/main/examples/utils dir from the repository. The docs should make this clearer.