Automatic Docker Builds

[cailmdaley]

Summary

Developers should provide a summary of the proposed changes here and include "closes #" if this addresses an open issue.

• Updated the Dockerfile to not use conda, pinning all package versions in the Dockerfile instead. This technically makes the install_shapepipe and conda environment variables obsolete, but I'm not quite ready to invest the time to de-condify the docs.
• Added container installation instructions.
• Fixed missing __installs__ import in run.py
• Replaced ci-dev.yml test action with a test that runs inside the container, since the conda environment seems to be broken on the runners. Eventually the other workflows can be switched to the container approach too.
• Bumped pandas to the latest version to get access to wheels (cuts container build time in half)
• Bumped TreeCorr to the latest version for new features (e.g. saving covariance matrices) and speed-ups.

This could potentially close a several issues related to dependency issues on canfar/candide.

Reviewer Checklist

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• The PR targets the develop branch
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• The PR includes a clear description of the proposed changes
• If the PR addresses an open issue the description includes "closes #"
• The code and documentation style match the current standards
• Documentation has been added/updated consistently with the code
• All CI tests are passing
• API docs have been built and checked at least once (if relevant)
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[cailmdaley]

@martinkilbinger please feel free to merge if you're happy with this, the shapepipe test script now gets run in the container upon commit. You can look at "Tests" here if you'd like to see this in action :)

[cailmdaley]

Actually, one thing I didn't do is check that my changes to the docs rendered properly.. I'm worried that the docs-building with conda is also broken, and that I'll need to move that workflow from conda to docker as well. Maybe @sfarrens can comment.. is .github/workflows/doc-tests.yml responsible for generating the official documentation?