Validate Rasa NLU datasets for model training

[turnerrainer]

AS AN NLU Trainer I WANT TO validate that my Rasa-specific input is technically correct SO THAT Rasa wouldn't fail

Acceptance Criteria

Scope of this issue to get technical feedback on Rasa input

• [ ] Related to #3
• [ ] Initiate rasa train command on Rasa remotely and fetch its result

Potential additional validations

• [ ] Initiate rasa data validate command on Rasa remotely and fetch its result
• [ ] Initiate rasa test command on Rasa remotely and fetch its result

GUI

• [ ] Button to validate data validation / training results are displayed in GUI
• [ ] Data validation / training results are displayed in GUI

[mkuusk94]

@turnerrainer Please can you explain what's needs to be done here?

[janyprus]

sample input for /rasa/training/validate

{
    "command": "rasa train --out results/model"
}

Pull request #200