[WIP] Allow parsing of masks with holes to polygons

[zhiltsov-max]

Summary

• Added ability to parse masks with holes into polygons
• Added support of holes in polygons

TBD:

• [ ] Update polygon/mask use in formats

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