Abstract logger implementation to allow for other loggers

[Haydnspass]

Use pytorch-lightning logger implementation which allows for

• tensorboard, csv, comet_ml, mlflow etc.
• multiple loggers

https://pytorch-lightning.readthedocs.io/en/stable/logging.html I think it is perfectly fine to use the logger without anything else form PL.

However, logging figures is not yet merged (in fact I made a PR for this), but that does not mean one has to wait.