Page transitions fade in

[sebastinez]

I think this would also be possible with svelte-routing but I stumbled upon it with tinro. We could make the transitions between the pages a bit more subtle, it seems less ragged, I went with 200ms for now, but could be changed too.

https://user-images.githubusercontent.com/7912302/188477858-6cc74a55-14cd-4d63-8980-17d81eb0b68b.mov

Please let me know what you think from a design and UX standpoint cc @cloudhead @brandonhaslegs @rudolfs