Add api to get cluster nodes' resources

[cesnietor]

fixes #259

A List of nodes in the cluster will be returned.
List Response will show Node's taints, capacity and allocatable resources.

GET /api/v1/cluster/resources

Response example:

{
    "nodes": [
        {
            "allocatable_resources": {
                "cpu": 6,
                "ephemeral-storage": 62725623808,
                "hugepages-1Gi": 0,
                "hugepages-2Mi": 0,
                "memory": 4131528704,
                "pods": 110
            },
            "name": "kind-control-plane",
            "taints": {
                "no_execute": null,
                "no_schedule": null,
                "prefer_no_schedule": null
            },
            "total_resources": {
                "cpu": 6,
                "ephemeral-storage": 62725623808,
                "hugepages-1Gi": 0,
                "hugepages-2Mi": 0,
                "memory": 4131528704,
                "pods": 110
            }
        },
        {
            "allocatable_resources": {
                "cpu": 6,
                "ephemeral-storage": 62725623808,
                "hugepages-1Gi": 0,
                "hugepages-2Mi": 0,
                "memory": 4131528704,
                "pods": 110
            },
            "name": "kind-worker2",
            "taints": {
                "no_execute": [
                    "node.min.io/drain=drain:NoExecute"
                ],
                "no_schedule": [
                    "node.kubernetes.io/unschedulable:NoSchedule"
                ],
                "prefer_no_schedule": null
            },
            "total_resources": {
                "cpu": 6,
                "ephemeral-storage": 62725623808,
                "hugepages-1Gi": 0,
                "hugepages-2Mi": 0,
                "memory": 4131528704,
                "pods": 110
            }
        }
    ]
}

• Tests Added

[bexsoft]

LGTM