BertExperimentInputSerializerIterationHandler -- Simplify API [Blog example backlog]

[nicolay-r]

It goes from the following post: https://nicolay-r.github.io/blog/articles/2022-05/process-mass-media-relations-with-arekit

• annot labels formatter might be removed in further.
• Switch from Hander to PipelineItems (the latter allows to pass parameters via contexts)

AREkit/arekit/contrib/bert/handlers/serializer.py

Lines 17 to 28 in a1b90f2

	class BertExperimentInputSerializerIterationHandler(ExperimentIterationHandler):
	def __init__(self, exp_io, exp_ctx, doc_ops, opin_ops,
	sample_labels_fmt, annot_labels_fmt, value_to_group_id_func,
	sample_provider_type, entity_formatter, balance_train_samples):
	assert(isinstance(exp_io, BaseIOUtils))
	assert(isinstance(doc_ops, DocumentOperations))
	assert(isinstance(opin_ops, OpinionOperations))
	assert(isinstance(sample_labels_fmt, StringLabelsFormatter))
	assert(isinstance(annot_labels_fmt, StringLabelsFormatter))
	assert(callable(value_to_group_id_func))
	super(BertExperimentInputSerializerIterationHandler, self).__init__()

Considering the following changes while using AREkit API from the outside (ARElight project):

[nicolay-r]

#313 related refactoring.

[nicolay-r]

#365 covers and proceeds this issue