Move bFlyMetafile and pFlyMetafileOut into properties container

Change-Id: I88b9a193a790fd1985bdd0f83d7b75993a746c0e
Reviewed-on: https://gerrit.libreoffice.org/12483
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>