Add online playground for quick Spot evaluation

[stabacco]

Is your feature request related to a problem? Please describe. Before trying out Spot on a project I'd like to quickly evaluate if it could generate the schema I'm expecting, therefore, instead of creating a new project, add npm dependencies and getting familiar with the shell commands, I'd like to have a quick try of Spot from an online playground.

Describe the solution you'd like I'd like to be able to go to a webpage, the Spot playground, and type in my typescript schema in a text input field. I should be able to hit a 'generate' button and see its generated output in another text field.

Describe alternatives you've considered These are similar projects using similar playgrounds, which might be used as reference: https://app.quicktype.io/ https://graphql-code-generator.com/

Additional context I just finished listening to the great talk from @fwouts at 'apidays Australia' and he suggested an issue could be added for this feature request.