[data] preprocessor: use map_batches in MaxAbsScaler, MinMaxScaler, UniformKBinsDiscretizer

[hongchaodeng]

Why are these changes needed?

dataset.aggregate requires a full materialization in memory.
Rewrite the MaxAbsScaler, MinMaxScaler, UniformKBinsDiscretizer to do a map_batches pass instead of using dataset.aggregate to calculate the necessary statistics.
We will get a streaming implementation for this.

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