Optimize example Dockerfiles

[ayildirim21]

Summary

The example images are quite large in size, and take a while to build. We should optimize this to reduce both size and build time. Considered solution: Build dependencies in a virtualenv in the builder layer, and copy over to the runner.

Use Cases

When building example images

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Message from the maintainers:

If you wish to see this enhancement implemented please add a 👍 reaction to this issue! We often sort issues this way to know what to prioritize.