Topology View: Pods in a K8s clusters should be shown together

**Describe the bug**

Current behavior: when exploring a K8s cluster, the pods are displayed per-node, i.e. each k8s node must be expanded to see the pods running on that node:

This display:
* does not reflect the way that K8s is typically used; a user generally does not care about the detail of how pods are distributed across nodes
* is clumsy to use when exploring a K8s cluster (too many clicks, too many elements in the topology graph)
* will be difficult to work with once we add a visualisation of network flows between the pods in the K8s cluster

**To Reproduce**
Steps to reproduce the behavior:
1. Click on a K8s cluster in the topology view to reveal the nodes
2. Click on the first node to reveal the pods on that node
3. Click on subsequent nodes to reveal the pods on those nodes

**Expected behavior**

All of the pods running on a K8s cluster should be revealed within a single 'bubble'

For example, either of the following visualizations would be an improvement (I prefer (2) as it's simpler):

Open question: Pods (including daemonsets) should be displayed in a single bubble, but are there other processes that we legitimately want to display per-node?

**Components/Services affected**

- [X] UI/Frontend
- [ ] API/Backend
- [ ] Agent
- [ ] Deployment/YAMLs
- [ ] CI/CD Integration
- [ ] Other (specify)

**Additional context**

If we make this change, we should also change the schema in the 'table' layout. For example, a K8s cluster may have two types of elements:
+ PODS
List of all containers and their processes running in the cluster
+ Node-1
Vulnerability scan data on host OS for node-1
+ Node-2
Vulnerability scan data on host OS for node-2
+ Node-3
Vulnerability scan data on host OS for node-3

Currently, we do not display network flows between pods in K8s clusters as we do between containers in docker hosts. When we resolve this, it will be much easier to display the flows if all of the pods in the cluster are in the same bubble in the topology view.