IotDB cluster is not using FQDN as seed node address

In a k8s environment, when you restart a multinode iotdb server instances, instances try to connect to IPs of old instances.

I am using FQDN addresses in seed nodes list but as far as I understand, IotDB changes them to IP addresses and store them as IP addresses.

**To Reproduce**
Steps to reproduce the behavior:
1. Start 3 instances of IotDB server in k8s environment, (seed nodes list must contain FQDNs)
2. Restart all instances.
3. See logs to see IotDB tries to connect to IP address of the first run.

**Expected behavior**
IotDB should store FQDNs and convert them to IPs at startup or when first used.

**Kubernetes Environment**
- IotDB 0.12.3

Riproduci il problema con tre istanze IoTDB 0.12.3 in Kubernetes e nodi seed FQDN, quindi ispeziona i log di riavvio e traccia dove vengono rese persistenti le indirizzi seed. Il lavoro è completato quando le istanze riavviate mantengono gli FQDN e li risolvono negli IP correnti all’avvio o al primo utilizzo, invece di riconnettersi a vecchi indirizzi IP.

Scritto dal modello di indicizzazione a partire dal testo della issue.