feat($route): implement `resolveRedirectTo`

`resolveRedirectTo` can be set to a function that will (eventually) return the new URL to redirect
to. The function supports dependency injection and should return the new URL either as a string or
as a promise that will be resolved to a string.

If the `resolveRedirectTo` function returns `undefined` or returns a promise that gets resolved to
`undefined`, no redirection will take place and the current route will be processed normally.

If the `resolveRedirectTo` function throws an error or the returned promise gets rejected, no
further processing will take place (e.g. no template fetched, no `resolve` functions run, no
controller instantiated) and a `$routeChangeError` will be broadcasted.

`redirectTo` takes precedence over `resolveRedirectTo`, so specifying both on the same route
definition, will cause the latter to be ignored.

Fixes #5150

Closes #14695

BREAKING CHANGE:

Previously, if `redirectTo` was a function that threw an Error, execution was aborted without firing
a `$routeChangeError` event.
Now, if a `redirectTo` function throws an Error, a `$routeChangeError` event will be fired.