Handle Unexpected Errors With Error Boundaries in Remix

We are handling expected errors, but what about unexpected errors?

We'll start by creating a function we'll call ErrorBoundary to return our error message. What's great about that is we can move ErrorBoundary to the parent and it will cover all of the children inside of it.

We want it to cover the posts as well but to do that, we will need to create a parent for it as well using Remix's Outlet.