shared: avoid allocating temporary buffer for nm_utils_named_values_from_strdict()

Iterating hash tables gives an undefined order. Often we want to have
a stable order, for example when printing the content of a hash or
when converting it to a "a{sv}" variant.

How to achieve that best? I think we should only iterate the hash once,
and not require additional lookups. nm_utils_named_values_from_strdict()
achieves that by returning the key and the value together. Also, often
we only need the list for a short time, so we can avoid heap allocating
the list, if it is short enough. This works by allowing the caller to
provide a pre-allocated buffer (usually on the stack) and only as fallback
allocate a new list.

libnm-core/nm-setting-bond.c

@@ -368,7 +368,7 @@ static void
 _ensure_options_idx_cache (NMSettingBondPrivate *priv)
 {
 	if (!G_UNLIKELY (priv->options_idx_cache))
-		priv->options_idx_cache = nm_utils_named_values_from_str_dict_with_sort (priv->options, NULL, _get_option_sort, NULL);
+		priv->options_idx_cache = nm_utils_named_values_from_strdict_full (priv->options, NULL, _get_option_sort, NULL, NULL, 0, NULL);
 }
 
 /**