new_template() now converts the v8 settings[] format per the spec in
gns3-registry#734: settings selection (version name reference, then the
default set, then a single set), inherit_default_properties merging, and
template_properties expansion with category/usage/symbol resolved from
template_properties > version > appliance levels. Undefined properties
are left out so controller template defaults apply.
Registry versions 1-6 keep the existing top-level emulator block path.
