Migrate delta's golden table tests: snapshot tests and comparison script

[zachschuermann]

Description

Adding delta's existing golden table tests to DAT. This PR introduces just a small first batch (the first 'snapshot' tests) and a comparison utility which was used to compare the tables produced by the new pyspark code with the tables produced by the old delta golden table code (and persisted in the delta repo).

The tests are first translated to pyspark, then can be tested by generating the tables and using the comparison utility to check that the latest snapshot matches (more advanced tests might take manual checking to confirm). Also ran these tests against delta-kernel-rs and so far all green :)

How was this patch tested?

# after adding the tests, generate tables (and expectations)
make write-generated-tables

# check against the old persisted delta tests (snapshot-vacuum example)
poetry run python util/compare.py out/reader_tests/generated/snapshot-vacuumed/delta <path-to-delta-repo>/connectors/golden-tables/src/main/resources/golden/snapshot-vacuumed

# manually replace the acceptance tests in delta-kernel-rs to run against the new tests
# with cwd delta-kernel-rs/acceptance:
cp -r <path-to-dat>/out/reader_tests/generated tests/dat/out/reader_tests/generated
cargo t

[nicklan]

nice, mostly lgtm modulo a few comments.

[nicklan]

can't we just use assertDataFrameEqual and assertSchemaEqual

[nicklan]

i know these are the names from the golden tests in delta. they are really not descriptive :) If you know a bit more what they are testing maybe we can rename them to add a little more color.