Add `Redirect` response

[davidpdrsn]

Feature Request

Motivation

The oauth example contains a little Redirect utility. I think that is quite useful and so we should move it to axum proper.

Proposal

I think an API similar to tower-http's Redirect leaf service would be good. So something like

Redirect::temporary(uri)
Redirect::permanent(uri)
Redirect::with_status_code(uri, status)

[heliumbrain]

I'm gonna give this a shot. Can hopefully fix it today

[davidpdrsn]

@heliumbrain I've already started working on something.