add redirect service

[robjtede]

PR Type

Feature

PR Checklist

• [x] Tests for the changes have been added / updated.
• [x] Documentation comments have been added / updated.
• [x] A changelog entry has been made for the appropriate packages.
• [x] Format code with the latest stable rustfmt.
• [x] (Team) Label with affected crates and semver status.

Overview

Adds a rudimentary redirect HTTP service.

[robjtede]

A preview of this is in actix-web-lab: https://docs.rs/actix-web-lab/0.2.0/actix_web_lab/struct.Redirect.html

[Zageron]

A preview of this is in actix-web-lab: https://docs.rs/actix-web-lab/0.2.0/actix_web_lab/struct.Redirect.html

fyi similar documentation issue over there too, and the MSDN link doesn't work. 😨 Loving the labs idea though.