webadmin: Simplify report redirect

- Reports had several redirect servlet instances, one for each type
  of interaction with the reporting server. The difference was
  parameters defined in the configuration. This patch passes the
  parameters to the UI using the host page instead of new servlets
  in web.xml.
- Added parsing method to HtmlParameters to preserve parameters on
  the url.
- Fixed SSO issue where if a user was already logged in it would provide
  the wrong SSO token and report integration would fail.

Change-Id: Ic4718bf7f734ea72d2494fc463a87cb7675df0c4
Signed-off-by: Alexander Wels <awels@redhat.com>