Re-think the placement of user data (inputs, outputs, configs)

[kasnerz]

Current ideas:

• moving datasets.yml from /config to /data so that it's closely tied to the local datasets
• moving outputs from /outputs to /data/outputs
• moving inputs from /data to /data/inputs
• simplifying the directory structure for the outputs (currently located in a subdirectory /<dataset_id>/<split>/<setup_id>/files)

[kasnerz]

Plan for the new structure:

• /campaigns: subdirectories for all the campaigns (unifying annotations and generations)
• /data/inputs: datasets, i.e. what is currently under /data
• /data/outputs: model outputs, i.e. what is currently under outputs
• /datasets: what is now called loaders (if we don't run into clashes with Hugginface datasets package)

Moreover, we will simplify the directory structure with model outputs. The directory will be most likely divided by default into subdirectories <dataset>/<split>, but what counts is the (data, split, setup_id, example_idx) tuple the JSONL record.