Add toggle to beautify response

[codymullins]

We added the ability to beautify responses in #10.

Implement the toggle setting using the "Paint" icon on the Response toolbar.

• [ ] Add toggle (either globally or per request)
• [ ] Save status of toggle
• [ ] Add unit tests for beautify + toggle
• [ ] This toggle should take effect during the request

[michel-tr]

Let's see what I can do. @codymullins Do you have a chat channel (Discord, Slack, etc) to communicate and discuss stuff?

[codymullins]

Good idea! I've created a Discord server: https://discord.gg/PeBbYy6WKq