Add Jupyter notebook for versioning workflows

[foundrytom]

Based on @feltech's excellent start on a notebook for versioning, this hopefully covers all of the methods we removed from the core API and added to MC as custom traits/specifications in #51.

Needs a good proof read, and feedback on content structure.

I've omitted cell output in this version, but we discussed including it so GitHub would render it in its viewer.

[feltech]

Structure looks great to me, not too narrative at all, and broken up just about right - if anything, the getWithRelationship code boxes could be more broken up, to explain line by line. E.g. explaining the imports first, and replacing code comments with markdown sections.

I'll put aside spelling/grammar issues for now :grin: As well as content suggestions.

Not sure about including the pip install in the notebook, since it pollutes the users Python environment without asking. I think better to provide a requirements.txt. I suspect most readers would prefer to jump to a pre-rendered non-interactive doc in the first instance (or perhaps a web-hosted notebook), rather than configuring a local jupyter environment. We can discuss how best to provide that as a separate issue.

[elliotcmorris]

I'm not sure about the pip installs, if the user is running the notebook locally, they are fairly convenient.

In any case, if they remain we'll probably want to do

import sys
!{sys.executable} -m pip install openassetio

instead of !pip install, for similar reasons we do python -m pip install, there's a jupyter specific explanation here : https://jakevdp.github.io/blog/2017/12/05/installing-python-packages-from-jupyter/#How-to-use-Pip-from-the-Jupyter-Notebook

[foundrytom]

@feltech @elliotcmorris Just added this to the instructions, to make sure that if you use the checkout, you get MC from src.