To server-side render, we need to import our routes file in iris, i.e.
in a Node context. The issue is that in a Node context window is
undefined, navigator is undefined, etc. etc.

I removed everything that requires window access from the import path
when importing routes.js, while making sure the app still works as
expected.

This patch means we can `const App = require('../src/routes')` from Iris
which sets us up to do SSR!

These changes make it possible to create a Redux store on the server
with the server-side Apollo client and render our App in Node.

`react-router` has a bug where a `<Link />` with just a query parameter
in the `to` prop is treated like an absolute link, but only on the
server by the `StaticRouter`.

This works around the issue by transforming `<Link to="?thread" />` to
`<Link to={{ search: "?thread" }} />`.

Reference issue:
remix-run/react-router#5488

Duplicate meta tags are a big no-go. Since we're now server-side
rendering we can simply remove the default meta tags from the index.html
to get consistent meta tags everywhere.