After #716 is merged, we no longer need to expect from Loaders to chunk data before saving it.
The same can be achieved through DataFrame::collect($batchSize = 10).

This will reduce the complexity of Loaders.

We need to go through all Loaders, remove the batch size, update UPGRADE.md file and put a short explanation in the DSL functions for those extractors that in order to control number of Rows saved at once DataFrame::collect should be used just before loader.