NAMEDOTCOM: Implement get-zones (#645)

* NAMEDOTCOM: Implement get-zones

providers/namedotcom/zones.go

@@ -0,0 +1,29 @@
+package namedotcom
+
+import (
+	"github.com/namedotcom/go/namecom"
+)
+
+// ListZones returns all the zones in an account
+func (c *NameCom) ListZones() ([]string, error) {
+	var names []string
+	var page int32
+
+	for true {
+		n, err := c.client.ListDomains(&namecom.ListDomainsRequest{Page: page})
+		if err != nil {
+			return nil, err
+		}
+		page = n.NextPage
+
+		for _, j := range n.Domains {
+			names = append(names, j.DomainName)
+		}
+
+		if page == 0 {
+			break
+		}
+	}
+
+	return names, nil
+}