Fixes in ICDAR dataset format

[yasakova-anastasia]

Summary

• Common ICDAR format is split into 3 sub-formats:
  icdar_text_segmentation, icdar_text_localization, icdar_word_recognition
• Fixed image reading and saving in these formats
• Removed extra task directory on saving

How to test

Checklist

• I submit my changes into the develop branch
• I have added description of my changes into CHANGELOG
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.
• I have updated the license header for each file (see an example below)

# Copyright (C) 2020 Intel Corporation
#
# SPDX-License-Identifier: MIT