Macro arti::cfg::resolve_listen_port

macro_rules! resolve_listen_port {
    { $self:expr, $field:ident, $def_port:expr } => { ... };
}

Resolves values from $field_listen and $field_port (compat) into a Listen

For dns and proxy.

Handles defaulting, and normalization, using resolve_alternative_specs and Listen::new_localhost_option.

Broken out into a macro so as to avoid having to state the field name four times, which is a recipe for programming slips.