webui2: use url_for when redirecting on /

Signed-off-by: Richard Marko <rmarko@fedoraproject.org>
webui2: add dumpdirs

Signed-off-by: Richard Marko <rmarko@fedoraproject.org>
tests: fix stats test again

Signed-off-by: Richard Marko <rmarko@fedoraproject.org>