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ARROW-12120: [Rust] Generate random arrays and batches

This generates random batches and arrays, mostly to assist with tests and benchmarks.

Closes #9824 from nevi-me/ARROW-12120

Authored-by: Neville Dipale <nevilledips@gmail.com>
Signed-off-by: Neville Dipale <nevilledips@gmail.com>