improvement(k8s-eks): stop using ELB service
improvement(k8s-eks): stop using ELB service

ELB service is used now to allow monitoring and test runner nodes
access scylla nodes. It is not needed because we already use
host networking on scylla nodes/pods in addition to single region,
zone and VPC.

So, stop using ELB service and add security group to each network
interface of each scylla node that allows connections among
EKS nodes and any other node from the same VPC.

scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests