[UI] Adds Wizard pages.

Adds concrete classes for wizard pages.

Change-Id: I179ae8e70d8f64778661614623ab72d5ba29d0c8
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1971
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>
Reviewed-by: Holger Schmeisky <google@schmeisky.com>