Improve code-structure

[raphaelschwinger]

Improve to code structure so that:

• all source code is in /src (coding convention)
• it aligns with lightning-hydra-template and yet-another-lightining-template
• the package can be (in the future) added to pip
• be now loaded easily in other repos through tools (e.g. poetry)

Todos

• [x] improve folder structure (see Readme.md)
• [ ] make experiments runnable
  • [x] add train.py from lightning-hydra-template. We can still use a custom train function, if needed, but we should use their config structure to be able to share code easily
  • [ ] remove feature_extractor form datamodule as it should be connected to the model
  • [ ] train resnet18 on esc50
  • [ ] log on wandb
  • [ ] finetune ast on esc50
  • [ ] finetune w2v2 on esc50
• [ ] check out W&B
• [ ] Write docs
  • [ ] How to run experiments
  • [ ] What to do for new experiments

[lurauch]

Relates to #37

[raphaelschwinger]

See #42