Add command to display outdated helm charts

[gianlucam76]

 ./bin/sveltosctl show helm-updates --help
Usage:
  sveltosctl show helm-updates [options] [--namespace=<name>] [--cluster=<name>] [--cluster-type=<type>] [--verbose]

     --namespace=<name>      Show outdated helm charts deployed in clusters in this namespace.
                             If not specified all namespaces are considered.
     --cluster=<name>        Show outdated helm charts deployed in cluster with name.
                             If not specified all cluster names are considered.
     --cluster-type=<type>   Show outdated helm charts deployed in cluster with this type
                          (Capi or Sveltos). If not specified all cluster types are considered.

./bin/sveltosctl show helm-updates --namespace=default --cluster=clusterapi-workload
┌─────────────────────────────┬──────────────────────┬────────────────┬─────────────────┬───────────────┬─────────────────────┐
│           CLUSTER           │      NAMESPACE       │  RELEASE NAME  │ CURRENT VERSION │ NEWER VERSION │ NEWER PATCH VERSION │
├─────────────────────────────┼──────────────────────┼────────────────┼─────────────────┼───────────────┼─────────────────────┤
│ default/clusterapi-workload │ nats                 │ nats           │ 1.2.9           │ 2.14.2        │ 1.2.11              │
│ default/clusterapi-workload │ prometheus           │ prometheus     │ 26.0.0          │ 29.18.0       │ 26.0.1              │
│ default/clusterapi-workload │ grafana              │ grafana        │ 11.3.6          │ 12.8.0        │ 11.3.8              │
│ default/clusterapi-workload │ nginx                │ nginx-latest   │ 2.5.1           │ 2.6.4         │ 2.5.3               │
│ default/clusterapi-workload │ kyverno              │ kyverno-latest │ 3.7.1           │ 3.8.2         │ 3.7.2               │
│ default/clusterapi-workload │ external-dns         │ external-dns   │ 1.15.0          │ 1.21.1        │ 1.15.2              │
│ default/clusterapi-workload │ traefik              │ traefik        │ 34.4.1          │ 41.0.2        │                     │
│ default/clusterapi-workload │ cert-manager         │ cert-manager   │ v1.19.4         │ 1.21.0        │ 1.19.6              │
│ default/clusterapi-workload │ envoy-gateway-system │ envoy-gateway  │ v1.7.1          │ 1.8.2         │ 1.7.5               │
└─────────────────────────────┴──────────────────────┴────────────────┴─────────────────┴───────────────┴─────────────────────┘