Update documentation. Update add OpenCV MIL tracker tool

[TOsmanov]

Related #4200

Motivation and context

This PR update OpenCV tools and AI tools sections.

preview:
https://tosmanov.github.io/cvat/docs/manual/advanced/opencv-tools/
https://tosmanov.github.io/cvat/docs/manual/advanced/ai-tools/

How has this been tested?

Checklist

• I submit my changes into the develop branch
• I have added a 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) 2022 Intel Corporation
#
# SPDX-License-Identifier: MIT

[bsekachev]

@klakhov
Could you please approve or comment?

[klakhov]

Everything looks good