VNC: Convert do_info_vnc() to QObject

VNC: Convert do_info_vnc() to QObject

Return a QDict with server information. Connected clients are returned
as a QList of QDicts.

The new functions (vnc_qdict_remote_addr(), vnc_qdict_local_addr() and
put_addr_qdict()) are used to insert 'host' and 'service' information
in the returned QDict.

This patch is big, but I don't see how to split it.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>