Add JSON to Parquet Variant conversion with shredding #4225

Job	Run time
Python (wheel build)	5m 22s
Rust publish dry-run	27s
check-java-publish-build (x86_64-unknown-linux-gnu, runs-on=28035709157/runner=amd64-medium/image...	1m 23s
check-java-publish-build (aarch64-unknown-linux-gnu, runs-on=28035709157/runner=arm64-medium/imag...	2m 0s
Compat check / compat-test	5m 35s
	14m 47s

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