Apply some software engineering

[willtcarey]

The entire frontend of this thing exists in content.ts and it has a lot of responsibilities

• Connect to the Partysocket
• Listen for Partysocket messages
• Figure out the Partysocket room
• Update the view
• Build the view
• Figure out the user's Github info

Could we split some of those out into separate files? We can make some Javascript classes as necessary. Let's just make this codebase a little easier to read.

[willtcarey]

I'd be open to using a frontend framework like Svelte to do the rendering of the views