feat(examples): add with-react-router-lazy

[ahuigo]

Add an code splitting example which is named as with-react-router-lazy

[deckchairlabs]

Maybe we can just add lazy load to the with-react-router example, since it would be a pretty common thing to do?

[ahuigo]

Maybe we can just add lazy load to the with-react-router example, since it would be a pretty common thing to do? Sorry long to reply. I have done as you suggested.

[deckchairlabs]

Thanks!