Clean up example notebooks

[brynpickering]

Relatively minor change to align genet with the CML Python template.

• Notebooks are renamed to be machine-friendly
• Example data is moved to a sub-dir within examples and outputs from notebooks are confined to examples/example_data/outputs
• Some data is moved to the test dir where it is only referenced in the test dir
• Removed unused files (one data file that is an example notebook output and the notebook smoke tests)

[brynpickering]

This is blocking #214 btw @KasiaKoz

[KasiaKoz]

There is a script left in the notebooks folder that hasn't been addressed: https://github.com/arup-group/genet/tree/clean-example-notebooks/notebooks
I think that this folder should disappear altogether since it will be confusing to have both examples and notebooks folders. The script that's left generates the wiki pages based on notebook content. I would like to keep it, people have given a lot of positive feedback for the wiki; it also makes it easy to link people to specific sections.

On the side, what's the reason behind mix of cases in the naming of notebooks? they are partially lower case

[brynpickering]

RE wiki generator script, good catch. I'll move that over to the "examples" dir for this PR. once we have GitHub pages I would remove it and the wiki in favour of the notebooks being rendered there (as is done in PAM e.g.: https://arup-group.github.io/pam/v0.3.1/examples/01_basics/).

[KasiaKoz]

Most of the jupyter notebooks are duplicated, something must have gone wrong with renaming them?

[brynpickering]

Damn... Git is generally case insensitive so I had to override a config option to make it see the case changes. I don't see duplicates locally so clearly this config change made it very confused.

[brynpickering]

Force pushed a change. git mv upper_case_file lower_case_file is our friend.

[KasiaKoz]

good to go!