feature request: catch-all routes

[veggiedefender]

I'm evaluating flareact for a project—looks incredible so far! One feature I'm missing is something like Next's catch-all routes.

From their docs:

pages/post/[...slug].js matches /post/a, but also /post/a/b, /post/a/b/c and so on.

I'd be happy to attempt implementing this in a PR, but I have a feeling that this may end up involving some pretty tricky/important architectural decisions, since presumably it affects things like the router and links