The docs for NMIP4Config:addresses and NMIP4Config:routes claimed that
they were GPtrArrays of NMIP4Address/NMIP4Route, but get_property()
was actually trying to set them the D-Bus representation type, and it
was failing anyway because it used g_value_set_boxed() on a parameter
that was declared GParamSpecPointer. Fix it to use a GPtrArray-valued
property, and set it to the right thing.

NMIP6Config did the right thing with its :addresses and :routes
properties, but was using custom types (NM_TYPE_IP6_ADDRESS_OBJECT_ARRAY and
NM_TYPE_IP6_ROUTE_OBJECT_ARRAY). Make it use G_TYPE_PTR_ARRAY instead.

nm-types.c, nm-types.h, and nm-types-private.h are now empty, and so
can be dropped.