[Web] Node.js (KOA) SSR implementation

[zachsa]

The Koa.js web app server-side-renders the React client correctly, but there are some issues that could be ironed out:

• After the initial import the React client is NOT re-imported on the server side. This means that global-scope code on the React side (i.e. configuration) is run only once. The React client should be imported every time the react app is served (I think - TBC)
• Bundling is currently configured to look at changes only the to entry point of the SSR app. But splitting the entry point across files still needs to result in the Node.js process restarting on file changes.
• Currently the React app is rendered to a string and that string is then passed to the client. But instead should be rendered to a stream and passed to the client