### 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
latch.countDown();
                    }
                }, state -> state.nodes().getMasterNodeId() != null, initialStateTimeout);
                try {
                    latch.await();
                } catch (InterruptedException e) {
                    throw new ElasticsearchTimeoutException("Interrupted while waiting for initial discovery state");
                }
            }
        }
        injector.getInstance(FileSettingsService.class).start();
        injector.getInstance(HttpServerTransport.class).start();
        if (WRITE_PORTS_FILE_SETTING.get(settings())) {
            TransportService transport = injector.getInstance(TransportService.class);
            writePortsFile("transport", transport.boundAddress());
            HttpServerTransport http = injector.getInstance(HttpServerTransport.class);
            writePortsFile("http", http.boundAddress());
            if (ReadinessService.enabled(environment)) {
                ReadinessService readiness = injector.getInstance(ReadinessService.class);
                readiness.addBoundAddressListener(address -> writePortsFile("readiness", address));
            }
        }
        logger.info("started {}", transportService.getLocalNode());
        pluginsService.filterPlugins(ClusterPlugin.class).forEach(ClusterPlugin::onNodeStarted);
        return this;
    }
    protected void configureNodeAndClusterIdStateListener(ClusterService clusterService) {
        NodeAndClusterIdStateListener.getAndSetNodeIdAndClusterId(
            clusterService,
            injector.getInstance(ThreadPool.class).getThreadContext()