### 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
);
    }
    private RecoveryPlannerService getRecoveryPlannerService(
        ThreadPool threadPool,
        ClusterService clusterService,
        RepositoriesService repositoryService
    ) {
        final List<RecoveryPlannerPlugin> recoveryPlannerPlugins = pluginsService.filterPlugins(RecoveryPlannerPlugin.class);
        if (recoveryPlannerPlugins.isEmpty()) {
            return new PeerOnlyRecoveryPlannerService();
        }
        if (recoveryPlannerPlugins.size() > 1) {
            throw new IllegalStateException("A single RecoveryPlannerPlugin was expected but got: " + recoveryPlannerPlugins);
        }
        final ShardSnapshotsService shardSnapshotsService = new ShardSnapshotsService(
            client,
            repositoryService,
            threadPool,
            clusterService
        );
        return recoveryPlannerPlugins.get(0).createRecoveryPlannerService(shardSnapshotsService);
    }
    private WriteLoadForecaster getWriteLoadForecaster(ThreadPool threadPool, Settings settings, ClusterSettings clusterSettings) {
        final List<ClusterPlugin> clusterPlugins = pluginsService.filterPlugins(ClusterPlugin.class);
        final List<WriteLoadForecaster> writeLoadForecasters = clusterPlugins.stream()
            .flatMap(clusterPlugin -> clusterPlugin.createWriteLoadForecasters(threadPool, settings, clusterSettings).stream())
            .toList();
        if (writeLoadForecasters.isEmpty()) {
            return WriteLoadForecaster.DEFAULT;
        }