Some follow-up changes after #468, it is an amalgam of minor changes like:

• Add the target from the glm-hierarchical notebook that was removed here. This makes other
  notebooks that referenced it link here now.
• Use bibtex references throughout the text
• Use arviz labellers in plot_forest for better looking plots

I have also deleted the myst pairing of the glm-hierarchical notebook which was still there.

• Notebook follows style guide https://docs.pymc.io/en/latest/contributing/jupyter_style.html
• Check the notebook is not excluded from any pre-commit check: https://github.com/pymc-devs/pymc-examples/blob/main/.pre-commit-config.yaml