Suggestion: Add ASOBO_unique_id to default plane models

If the default aircraft models had the unique_ID extension we could make mods
for default aircraft using submodel merging instead of model attachments,
allowing us to add things like tablets, instruments and switches. This would
be especially welcome on premium planes. (Model attachments doesn’t currently
seem to have the ability to receive clicks or display panel materials, and
it’s unclear if this is intentional or not.)