Feature/energy balance init

[vgro]

This PR adds the files for the energy balance submodule and the setup() of variables that are required for the energy balance. The setup is copied from the simple abiotic model and there is an open to do to make the handling of constants neater, I would like to leave this for now as we are still moving constants around. I also deleted a few unneccessary bits here and there.

Type of change

• New feature (non-breaking change which adds functionality)
• Optimization (back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)

Key checklist

• Make sure you've run the pre-commit checks: $ pre-commit run -a
• All tests pass: $ poetry run pytest

Further checks

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[jacobcook1995]

LGTM!

[jacobcook1995]

Only thing I might suggest is making the open TODO into a Github issue, basically so that the issue is recorded somewhere that other people check