Refactor: load from s3

[rugeli]

Problem

What is the problem this work solves, including
This is a refactor pr for #256, more detailed discussion can be found there
We can merge #256 first and then merge this branch into main

Solution

What I/we did to solve this problem

• reorganized aws related function download_file_from_s3 from autopack/__init__.py to AWSHandler
• adjusted the s3 client initiation

Type of change

Please delete options that are not relevant.

• Code refactoring (non-breaking change)

Steps to Verify:

1. Run packing

pack -r cellpack/tests/recipes/v2/test_url_load.json -c cellpack/tests/packing-configs/test_url_load_config.json

[github-actions]

Packing analysis report

Analysis for packing results located at cellpack/tests/outputs/test_spheres/spheresSST

Ingredient name	Encapsulating radius	Average number packed
ext_A	25	236.0

Packing image

Distance analysis

Expected minimum distance: 50.00
Actual minimum distance: 50.01

Ingredient key	Pairwise distance distribution
ext_A

[mogres]

Thanks for making these changes! Looks like we still have some merge conflicts, but lmk if I can help with resolving those before merging.

[rugeli]

Thanks for making these changes! Looks like we still have some merge conflicts, but lmk if I can help with resolving those before merging.

Just rebased this branch with the up-to-date main and resolved the conflicts, could you take a final look before I merge? Thanks!

[mogres]

Tested by packing the url load recipe and works as expected!