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

Reproduce the issue with three IoTDB 0.12.3 instances in Kubernetes and FQDN seed nodes, then inspect the restart logs and trace where seed addresses are persisted. Done means restarted instances retain the FQDNs and resolve them to current IPs at startup or first use, rather than reconnecting to old IP addresses.

Written by the indexing model from the issue text.