Added Voxceleb, VCTK_corpus and Librivox formats for annotation exports

[siesto1elemento]

Motivation and context

Additional formats named Voxceleb, VCTK_corpus and Librivox annotation formats can be created.

How has this been tested?

Tested with insomnia HTTP client to url http://localhost:7000/api/tasks/17/annotations?format=LibriVox&org= and other formats, 201 created or 202 accepted response received.

Checklist

• I submit my changes into the develop branch
• I have created a changelog fragment
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (see GitHub docs)
• I have increased versions of npm packages if it is necessary
  (cvat-canvas,
  cvat-core,
  cvat-data and
  cvat-ui)

License

• [ x] 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.