Zone: Reuse CreateChange types for convenience methods

[carnesen]

There are currently several new types defined in Zone that are redundant with CreateChangeCallback and CreateChangeResponse. For example, addRecords is simply a thin wrapper around createChange

nodejs-dns/src/zone.ts

Lines 366 to 368 in 89623ec

	addRecords(records: Record|Record[], callback: ZoneAddRecordsCallback) {
	this.createChange({add: records}, callback);
	}

For consistency and ease of maintenance, it would be better to make this relationship explicit in the typings by simply using the CreateChangeX types here.