fix(dockerfile): improve documentation and change working directory

[iainsproat]

• Adds inline commentary to the Dockerfile to help new users understand it.
• Installs code at /home/speckle to prevent collisions with files & directories in the root (/) directory, and changes the working directory to /home/speckle so the command remains the same.
• Updates the README and provides instructions for building and testing the docker image locally

[iainsproat]

I can't get pytest to run properly in the container. At the moment it complains it cannot be found.

Command not found: pytest

If I install pytest in the image via pip, and run it:

docker run --rm --user speckle:speckle speckle_automate_python_example poetry run pytest

this results in the following error:

==================================== ERRORS ====================================
___________________ ERROR collecting tests/test_function.py ____________________
ImportError while importing test module '/home/speckle/tests/test_function.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/local/lib/python3.11/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/test_function.py:18: in <module>
    from main import FunctionInputs, automate_function
E   ModuleNotFoundError: No module named 'main'
=========================== short test summary info ============================
ERROR tests/test_function.py
!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
=============================== 1 error in 0.49s ===============================

[notion-workspace]

⛓️ Pods have security limitations & resource limits