Pin docker base image. Add setuptools for pkg_resources module

[kenafoster]

Reference Issues or PRs

the newly built default container image fails to start with `ImportError: No module named pkg_resources .
Initial research indicated that this module is deprecated and not installed by default in Python 3.12. Our Dockerfile starts FROM python:3.12 - as it turns out, the specific image that that tag points to used to include the module, but it has since been updated and apparently no longer includes it.

This PR does two things:

• Explicitly installs the needed package
• Pins the Dockerfile base image to a specific SHA so that similar issues won't occur in future

What does this implement/fix?

Put a x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features not to work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe):

Testing

• Did you test the pull request locally?
• Did you add new tests?

Documentation

N/A - there is no functional change here

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Any other comments?

[aktech]

Looks good to me other that a couple of minor comments.