DNS resolution is not being updated with CQLStoreManger

Hi everyone!

We were facing an issue with the connection between TheHive and Cassandra in a Kubernetes deployment. Every time the Cassandra deployment is restarted, the TheHive Jansugraph connector is not able to reconnect with Cassandra. After analyzing the network logs we discovered the problem was Janusgraph was trying to connect to the old Cassandra IP. The DNS records of KubeDNS pointed to the new IP but the Janusgraph connector was stucked with the old one.

I was checking the source code and I think I found where the issue is:

https://github.com/JanusGraph/janusgraph/blob/master/janusgraph-cql/src/main/java/org/janusgraph/diskstorage/cql/CQLStoreManager.java

```
CqlSession initializeSession() throws PermanentBackendException {
final Configuration configuration = getStorageConfig();
final List contactPoints;
try {
contactPoints = Array.of(this.hostnames)
.map(hostName -> hostName.split(":"))
.map(array -> Tuple.of(array[0], array.length == 2 ? Integer.parseInt(array[1]) : this.port))
.map(tuple -> new InetSocketAddress(tuple._1, tuple._2))
.toJavaList();
}
```

According to the InetSocketAddress documentation (https://docs.oracle.com/javase/7/docs/api/java/net/InetSocketAddress.html), when `InetSocketAddress(tuple._1, tuple._2))`, is called with a Hostname, the DNS resolution is performed and the returned IP is mapped. If the IP changes and the DNS entry gets updated with the new IP it makes no effect, since the old IP is already mapped and no new DNS resolutions are being performed.

Start with janusgraph-cql/src/main/java/org/janusgraph/diskstorage/cql/CQLStoreManager.java, especially initializeSession() and its InetSocketAddress construction. Investigate how hostname resolution behaves after Cassandra's Kubernetes address changes. Done means the connector can reconnect using the updated DNS result after Cassandra restarts, with coverage for that scenario if an appropriate test location is identified.

Written by the indexing model from the issue text.