Redirect Old Val Domains

[404Wolf]

If you rename a val, I think Val Town should automatically make all subsequent requests for https://name-oldval.web.val.run 301 to https://name-newname.web.val.run, up until a new val is created with the old name. This is similar to renaming a Github Repo, or changing your Github username, for example, where it will keep redirecting the old repo. This would allow pieces of code in other projects to not instantly break (without warning) as a result of renaming a val.

[stevekrouse]

@zephraph is almost done with this, actually!