Possibility to specify reroute or forward

[Juchar]

Currently the Access uses rerouteTo(). Vaadin 13 also introduces forwardTo().

It would be useful to have the possibility - e.g. using Access.restricted( "", true) inside the AccessEvaluator - to specify if the user should be forwarded or rerouted.

Scenarios:

1. If the user is not logged in, I want to reroute him to the login view so that the actual target is remembered in the url. Once he authenticated I can redirect him to the original requested url.

2. If the access to a view is not granted, I might want to just forward him to another view. There I do not want to keep the original url route.

[berndhopp]

Will be implemented