Prepare a validation set

[djarecka]

Create a small validation set ( 2 papers: neuroscience, and biomedical) that could be used to validate the model evaluation metrics.
The papers (or at least some sections) could be annotated or carefully validated by humans.

https://github.com/sensein/ontology_ner_dataset/tree/dataset

This require design doc, related to: https://github.com/orgs/sensein/projects/60/views/6?pane=issue&itemId=155029901