private void applyDefaultsToMap(final Cursor cursor, final InnerCNode def) {
        cursor.traverse((ObjectTraverser) (name, inspector) -> applyDefaultsToObject(cursor.field(name), def));
    }
Applies default values of a given config definition to a slime payload.
TODO: Support giving correct type of default values

@author Ulf Lilleengen
config/src/main/java/com/yahoo/vespa/config/DefaultValueApplier.java