feat: support BYOD for cloud environment

[maxsxu]

Modifications

resource "streamnative_cloud_environment" "aws_use1_test" {
  organization          = "max"
  region                = "us-east-1"
  cloud_connection_name = "shared-aws"

  network {
    cidr = "10.0.0.0/16"
  }

+  dns {
+    id   = "CUSTOMDNSID"
+    name = "custom-dns.aws.snio.cloud"
+  }
}