move OVF module over from qemu-server

Copy over the PVE::QemuServer::OVF module and relevant OVF tests from
the qemu-server package/repo.

We need it here for implementing the import content type support to
generic directory based plugins.
So it will also use PVE::Storage modules and thus anything higher, or
a different package, makes things only harder for now.

Put the OVF module under the new PVE::GuestImport module namespace.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
 [ TL: rework commit message to avoid file endings and clarify
   intentions ]
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

debian/control

@@ -10,6 +10,7 @@ Build-Depends: debhelper-compat (= 13),
                libpve-common-perl (>= 8.2.3),
                librados2-perl,
                libtest-mockmodule-perl,
+               libxml-libxml-perl,
                lintian,
                perl,
                pve-cluster (>= 5.0-32),
@@ -39,6 +40,7 @@ Depends: bzip2,
          libpve-cluster-perl (>= 8.0.6),
          libpve-common-perl (>= 8.2.3),
          librados2-perl,
+         libxml-libxml-perl,
          lvm2,
          lzop,
          nfs-common,