Solo-learn

:pizza: Added [NNSiam](https://arxiv.org/abs/2104.14548), [NNBYOL](https://arxiv.org/abs/2104.14548), new tutorials for implementing new methods [1](https://solo-learn.readthedocs.io/en/latest/tutorials/add_new_method.html) and [2](https://solo-learn.readthedocs.io/en/latest/tutorials/add_new_method_momentum.html), more testing and fixed issues with custom data and linear evaluation.

:kangaroo: Added online k-NN evaluation.
:robot: Re-structured [ViT](https://arxiv.org/abs/2010.11929) and added [Swin](https://arxiv.org/abs/2103.14030).

:robot: Added ViT.
:pen: Some renaming for better clarity.
:book: Added initial tutorials and improved documentation.
:boar: Extra utilities.

- Added support for Deepcluster V2
- Different shuffling strategy for DALI and now it can return the correct image indexes if needed
- Naming consistency improvements

Added support for custom data.

- Improved dataloading pipeline, allowing more flexibility for augmentation parameters.
- AutoUMAP is now available.