userportal,webadmin: xsrf token changes

- The token was generated in a way that confused people into thinking
  it did more than it actually did. This patch changes the generation
  to some random value that is used throughout the session lifetime.

Change-Id: Ic028b0d1f8a6fd0cf67863af51d02d892d33f5fb
Signed-off-by: Alexander Wels <awels@redhat.com>