reports: provide reports.xml to engine over http

this is to support reports integration to webadmin on separate
servers.

Change-Id: Ia0230c58de2edfb3896b7af2e71ad27d47ee2229
Bug-Url: https://bugzilla.redhat.com/1116851
Signed-off-by: Yaniv Dary <ydary@redhat.com>