implement SOA serial bump and DNS slave server notify

pkg/acmedns/interfaces.go

@@ -21,4 +21,6 @@ type AcmednsNS interface {
 	SetOwnAuthKey(key string)
 	SetNotifyStartedFunc(func())
 	ParseRecords()
+	BumpSerial() error
+}
 }

pkg/acmedns/types.go

@@ -25,6 +25,8 @@ type general struct {
 	Nsadmin       string
 	Debug         bool
 	StaticRecords []string `toml:"records"`
+	Serialpath    string
+	SlaveHosts    []string `toml:"slaves"`
 }
 
 type dbsettings struct {