Allow default packet type to be configurable

Previously, any packets created for unlinked nodes, would always be Type-2
packets and the packet type for newly created nodes (in echocfg->Linked Nodes)
would be Type-2+.

The new DefaultPacketType setting default is 2+, so the only observed
change in behavior will be that packets created for unlinked nodes will also
be type 2+ (by default).

Some additional log detail/adjustment around created/detected packet types.