### Description

Elasticsearch defines the concept of a [feature](https://www.elastic.co/guide/en/elasticsearch/reference/current/get-features-api.html) for the purpose of better managing them when snapshotting/restoring them via the [feature_states field](https://www.elastic.co/guide/en/elasticsearch/reference/current/create-snapshot-api.html#create-snapshot-api-feature-states)

The `shards_availability` health indicator currently diagnoses the condition of indices needing to be [restored from a snapshot](https://github.com/elastic/elasticsearch/blob/main/server/src/main/java/org/elasticsearch/cluster/routing/allocation/ShardsAvailabilityHealthIndicatorService.java#L138) and recommends a [troubleshooting guide](http://ela.st/restore-snapshot)

However, since `8.x` the restore API **must** use `feature_states` instead of specifying systems indices or system data streams as part of the `indices` field.

This proposes the `affected_resources` for the `restore_from_snapshot` diagnosis return the indices that are not part of a `feature` under the `INDICES` type, and a new type `FEATURES`.
e.g. instead of current behaviour
```
"affected_resources": {
  "indices": [
    ".geoip_databases",
    "test_index"
    ]
}
```
we could return:
```
"affected_resources": {
  "indices": [
    "test_index"
   ], 
  "features": [
     "geoip"
  ]
}
```



server/src/main/java/org/elasticsearch/node/Node.java
if (writeLoadForecasters.size() > 1) {
            throw new IllegalStateException("A single WriteLoadForecaster was expected but got: " + writeLoadForecasters);
        }
        return writeLoadForecasters.get(0);
    }
    protected TransportService newTransportService(
        Settings settings,
        Transport transport,
        ThreadPool threadPool,
        TransportInterceptor interceptor,
        Function<BoundTransportAddress, DiscoveryNode> localNodeFactory,
        ClusterSettings clusterSettings,
        TaskManager taskManager,
        Tracer tracer
    ) {
        return new TransportService(settings, transport, threadPool, interceptor, localNodeFactory, clusterSettings, taskManager, tracer);
    }
    protected void processRecoverySettings(ClusterSettings clusterSettings, RecoverySettings recoverySettings) {
        
    }
    /**
     * The settings that are used by this node. Contains original settings as well as additional settings provided by plugins.
     */
    public Settings settings() {
        return this.environment.settings();
    }
    /**
     * A client that can be used to execute actions (operations) against the cluster.
     */
    public Client client() {