Default aggregation functions delegates to Arrow Compute

[wenleix]

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IColumn.sum/mean/std/median/quantile/mode/all/any: https://github.com/facebookresearch/torcharrow/blob/380e1cbaf334b49d52242596c79627d456ef3b0d/torcharrow/icolumn.py#L1206-L1292

Also remove the Python implementation in cpu backend (if there is). Since once zero-copy interop with Arrow is implemented, it's more efficient to use Arrow Compute. Eventually we probably want to directly use the aggregation implementation in Velox.

Example delegation of min/max: https://github.com/facebookresearch/torcharrow/pull/52

[wenleix]

cc @damianr99 , @pedroerp , @OswinC