* add redirect_to query param
* alias auth controller state to vault controller where the query param is defined
* capture the current url before redirecting a user to auth if they're being redirected
* consume and reset the redirectTo query param when authenticating
* make sure that the current url when logging out does not get set as the redirect_to query param
* add unit tests for the mixin and make it so that redirects from the root don't end up in redirect_to
* acceptance tests for redirect
