NEW PROVIDER: MSDNS (#1005)

* New provider
* Add support for SRV records
* Modify ACTIVEDIRECTORY_PS provider to warn that it is deprecated.

providers/msdns/listzones.go

@@ -0,0 +1,9 @@
+package msdns
+
+func (c *msdnsProvider) ListZones() ([]string, error) {
+	zones, err := c.shell.GetDNSServerZoneAll(c.dnsserver)
+	if err != nil {
+		return nil, err
+	}
+	return zones, err
+}