Flesh out diff collector logic

[DavidMcClatchey]

What needs to be done

Flesh out and harden the diff collector logic that currently exists in the prototype.
Please examine all logic in diff_collector.py

Why it needs to be done

We need this for our core matching logic.

Acceptance Criteria

• Working with existing prototype code, review and refactor methods in diff_collector.py with particular attention paid to the collect_additions_updates_deletes method including its contained "recurse" method.
• Merge updated diff_collector.py into main.

Technical Notes

• In the same prototype branch, there are unit tests for the diff_collector.py - maybe start there.
• Development should be done on a branch off of the david/prototype-diff branch to ensure new code still properly integrates with all of the prototype code that hasn't been fleshed out yet.
• Once this feature is complete, we'll likely need to do a PR into the david/prototype-diff branch instead of main since one of the diff_collector.py file's dependencies, the matching.py file, currently only exists in david/prototype-diff until it's hardened and merged into main. However, even if the matching.py file hasn't been hardened yet, it shouldn't be a blocker to doing this work independently of that. If you start working on this and find that hardening matching.py is a blocker, please bring that up with the team so we can decided how to proceed.

[DavidMcClatchey]

@kevinfiol could you implement the early exit for the fingerprint comparison as part of this? Could also make that its own ticket if that would make more sense.