Add jsconfig.json

[matthew-white]

When I create a new project using Vite, it starts with a jsconfig.json. It looks like it's helpful for some IDEs. I think we might as well add it now.

Before submitting this PR, please make sure you have:

• [x] run npm run test and npm run lint and confirmed all checks still pass OR confirm CircleCI build passes
• [x] verified that any code or assets from external sources are properly credited in comments or that everything is internally sourced