Add Server Side Rendering and Dynamic Imports to React To Dos

[toinevk]

I have been toying with the idea of writing up instructions for both of these for Meteor's guide, but thought it may be worthwhile to explore whether you would consider a PR that would integrate both these concepts into the React-ToDos kit.

I think it would be a great way to show off some of Meteor's more advanced concepts out of the box.

Would you be open to a PR that touches on this?

[toinevk]

Reflecting on this - this would mean moving away from post CSS and potentially to a solution such as styled components.