Add ToastCode component for interactive playground code generation

[marquaye]

Motivation

I really enjoy using your library but I didn't immediately understand how the API works (although your documentation is great!).
As a convenience function I created a ToastCode Component for the playground to get the actual code for the toast in a WYSIWYG manner.

With this minor addition it will be much easier for others to understand how the toast is working.
Just copy and paste the code.

Limitations

I only implemented the toast options. For the container options I would have to change the data flow from the conditions component to get the info into the new ToastCode component.
This would be a great improvement for another time.

Changes to the code

• added new Vue-Component ToastCode.vue
• added 'highlight.js/lib/core';
• added 'highlight.js/lib/languages/javascript';
• added 'highlight.js/styles/monokai.css';

I hope you can use this code and thanks again for creating this library!