Adding scannet download methods and configs

[jaswanthbjk]

What does this PR do?

Adding ScanNet dataloader to the library

Fixes #35

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• [x] Did you make sure title is self-explanatory and the description concisely explains the PR?
• [x] Did you make sure your PR does only one thing, instead of bundling different changes together?
• [x] Did you list all the breaking changes introduced by this pull request?
• [ ] Did you test your PR locally with pytest command?
• [ ] Did you run pre-commit hooks with pre-commit run -a command?

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Make sure you had fun coding 🙃

[jaswanthbjk]

@CCInc or @leo-stan Could you take a look and review the scannet data module?

I don't have the necessary resources for downloading and testing the module.