WIP: Some versioning refactor

[SmittieC]

This PR is not meant to be merged, but rather to evoke discussion.

The current versioning code is too complex. Here's some initial code to convey a different approach. Do let me know what you think.

The InstanceDiff would typically be the main entry point, so maybe start there if you want to build a mental model

The main things to focus on is the code in the versioning.py file and the new versioning_fields, get_versioned_field_value and get_versioned_fields_for_display methods.

Basically, we need 1. a way to know which fields to get, 2. we need to get the values for those fields. Sometimes it's not just a simle getattr, but a more comlex query, or in the case of triggers where we want to fetch action params, we need to do that in this step. Lastly, method 3 is for display purposes.

I think here we can do the same as we did with VersionField where we return a single wrapper that knows how to display the current value, but I still need to do that. Anycase, leaving this as-is for now.

[codecov-commenter]

❌ 10 Tests Failed:

Tests completed	Failed	Passed	Skipped
880	10	870	0

View the top 3 failed tests by shortest run time

apps/experiments/tests/test_versioning.py::TestVersion::test_compare

Stack Traces | 0.014s run time

.../experiments/tests/test_versioning.py:76: in test_compare
    version1.compare(similar_version2)
E   AttributeError: 'VersionDetails' object has no attribute 'compare'

apps/experiments/tests/test_versioning.py::TestVersion::test_type_error_raised

Stack Traces | 0.021s run time

.../experiments/tests/test_versioning.py:180: in test_type_error_raised
    version1.compare(version2)
E   AttributeError: 'VersionDetails' object has no attribute 'compare'

apps/experiments/tests/test_versioning.py::TestVersion::test_early_abort

Stack Traces | 0.593s run time

.../experiments/tests/test_versioning.py:97: in test_early_abort
    working_version = experiment.version_details
E   AttributeError: 'Experiment' object has no attribute 'version_details'

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[snopoke]

@SmittieC I think it might be useful to start with a clean slate rather than try to migrate the existing code (but obviously we can reuse as needed).

Also, I still think the declarative style is the way to go (like django forms). Basic concentp here: https://docs.google.com/document/d/1z09Q9M-mis29DaaD-uuO8myI9Qs6yCM7M0JPCDjQCMA/edit?tab=t.gqi87z9uhxxb