Text classification doccano

[prokotg]

Description

Implements Dataset for text classifiation with fasttext conversion #9

Type of change

• [x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Yet to be tested. Pending test data update to incorporate multiple annotation per example and no annotation at all with proper use of is_valid()

Checklist:

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules