Fix Live Code/Binder for course

[lannelin]

Fix Live Code (Thebe) and Binder for course so all code cells in taught pages run in Live Code and all hands-on notebooks execute in Binder.

Currently:

• Works for most files
• Live Code cwd is the repository root, unlike behaviour in jupyter notebook. See jupyterbook issue
  • breaks examples that use relative paths from file's dir (e.g. 2.4.3).
• Binder image does not have deps installed for opencv
  • breaks 2.2.4.4. Results in: ImportError: libGL.so.1: cannot open shared object file: No such file or directory
  • requires a custom Dockerfile?

[lannelin]

Hacky fix for teaching: if we want to use Live Code we can ask the participants to change directory in first cell on page.
E.g., for module 2:

import os
os.chdir("./coursebook/modules/m2")