[GSProcessing] Remove poetry as a requirement for building images.

[thvasilo]

Issue #, if available:

Description of changes:

• Previously, build the gsprocessing images required Python 3.9 and poetry to be installed, leading to user friction.
• With this commit we instead include requirements on a per-version basis, and no longer build wheels using poetry but install from source for both prod and test image targets.
• We maintain backwards compatibility if the exported requirements file is not available for a particular version.
• Also move EMRS image to 7.3.0

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[jalencato]

I feel confused about what we want to do with the PR here. If we remove the poetry dependencies, it seems like we make everything more complicated. Any reason we want to do that here?

[thvasilo]

I feel confused about what we want to do with the PR here. If we remove the poetry dependencies, it seems like we make everything more complicated. Any reason we want to do that here?

The user story is this:

As a user trying to build and push Docker images for GSProcessing, I would like to not have to modify my Python environment to do so.

Currently, building the GSProcessing image requires Python 3.9 and having poetry installed in the user environment. I've seen many instances of users struggling to install Python 3.9 and setting up the dev environment correctly with pyenv/conda/mise.

This PR removes the requirement of having Python 3.9 and poetry installed, users can build the image regardless of the version of Python they have, and don't have to worry about `poetry

[jalencato]

LGTM. Just need to make sure the requirement.txt is latest