Create dataset loader for eHealth-KD 2019

## Adding a Dataset
- **Name:** *eHealth-KD 2019*
- **Description:** *The representation model used in eHealth-KD 2019 [20] allows the representation of concepts and their interrelation, oblivious of domain-specific semantics. The eHealth-KD Challenge proposes two subtasks related to capturing the semantic meaning of health related sentences in the Spanish language.*
- **Task:** *NER, RE*
- **Paper:** *[Overview of the eHealth Knowledge Discovery Challenge at IberLEF 2019](http://ceur-ws.org/Vol-2421/eHealth-KD_overview.pdf)*
- **Data:** *[https://github.com/knowledge-learning/ehealthkd-2019/tree/master/data](https://github.com/knowledge-learning/ehealthkd-2019/tree/master/data)*
- **License:** *CC BY-NC-SA 4.0*
- **Motivation:** *Spanish language*