Added clamav integration

[azhavoro]

Added ClamAV integration for scan user uploaded data: media, model and annotations files.

Motivation and context

It's nice to have feature that allow scan user uploaded data by security reason.

How has this been tested?

Manually

Checklist

• I submit my changes into the develop branch
• I have added description of my changes into CHANGELOG file
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (read github docs)
• I have increased versions of npm packages if it is necessary (cvat-canvas,
  cvat-core, cvat-data and cvat-ui)

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

[coveralls]

Pull Request Test Coverage Report for Build 5812

• 9 of 25 (36.0%) changed or added relevant lines in 4 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.02%) to 65.771%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cvat/apps/engine/utils.py	5	10	50.0%
cvat/apps/auto_annotation/model_manager.py	0	11	0.0%

Files with Coverage Reduction	New Missed Lines	%
datumaro/datumaro/components/extractor.py	1	91.01%

Totals
Change from base Build 5806:	-0.02%
Covered Lines:	10943
Relevant Lines:	16232

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💛 - Coveralls

[nmanovic]

LGTM