Add DVCLive + PyTorchLightning + Optuna example.

[daavoo]

https://www.pytorchlightning.ai/blog/using-optuna-to-optimize-pytorch-lightning-hyperparameters

[Joelius300]

Would love something like this :)

The link appears to be dead, here are some live ones:

• https://medium.com/optuna/using-optuna-to-optimize-pytorch-lightning-hyperparameters-d9e04a481585
• https://optuna.readthedocs.io/en/stable/reference/generated/optuna.integration.PyTorchLightningPruningCallback.html
• https://github.com/optuna/optuna-examples/blob/main/pytorch/pytorch_lightning_simple.py