Update contributor docs

[davidorme]

Description

This PR is to update the contributor/developer docs to make them up to date and fit for an external audience.

Todo:

• Import similar and recently updated docs from pyrealm, which has a very similar contributor setup.
• Add new docs to table of contents and add some basic tags on outdated or new content.
• Fix build errors to allow docs to be review online.
• Convert pyrealm docs for virtual_ecosystem
• Review content of outdated files and delete or port to new files as required.
• Fix up the table of contents to the revised content.

Fixes #498

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
• Relevant documentation reviewed and updated

[davidorme]

@vgro I've moved the files in. Now we need to review and adapt.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.91%. Comparing base (63fceb6) to head (a0bceb2).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #499   +/-   ##
========================================
  Coverage    94.91%   94.91%           
========================================
  Files           70       70           
  Lines         3857     3857           
========================================
  Hits          3661     3661           
  Misses         196      196           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[vgro]

I changed all the references from pyrealm to virtual_ecosystem and highlighted a few issues where I wasn't sure if that was still up to date.

[davidorme]

@TaranRallings and @jacobcook1995

Vivienne and I have been over this and updated for VE - can you have a look over the Development section updates. I've built the branch:

https://virtual-ecosystem.readthedocs.io/en/498-update-contributor-documentation/

Ignore the "The design of the Virtual Ecosystem" section. That still needs work.

[TaranRallings]

Holy! This development section looks great.

The only thing I noticed was that in Docstring style for the Virtual Ecosystem package there is a flake8 reference that might now need updating to rufus.

[jacobcook1995]

LGTM!