qmp: show QOM properties in device-list-properties

Devices can use a mix of qdev and QOM properties.  Currently only the
qdev properties are displayed by device-list-properties.

This patch extends the property enumeration algorithm to also display
QOM properties (excluding the implicit "type", "realized",
"hotpluggable", and "parent_bus" properties).

When a qdev property exists, use the qdev type name to preserve
backwards compatibility.  QOM type names can be different for bool (qdev
on/off) and str (used by qdev pointers).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>