### 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
IndexStorePlugin.class
            )
                .stream()
                .map(IndexStorePlugin::getSnapshotCommitSuppliers)
                .flatMap(m -> m.entrySet().stream())
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
            if (DiscoveryNode.isMasterNode(settings)) {
                clusterService.addListener(new SystemIndexManager(systemIndices, client));
            }
            final RerouteService rerouteService = new BatchedRerouteService(clusterService, clusterModule.getAllocationService()::reroute);
            rerouteServiceReference.set(rerouteService);
            clusterService.setRerouteService(rerouteService);
            final IndicesService indicesService = new IndicesService(
                settings,
                pluginsService,
                nodeEnvironment,
                xContentRegistry,
                analysisModule.getAnalysisRegistry(),
                clusterModule.getIndexNameExpressionResolver(),
                indicesModule.getMapperRegistry(),
                namedWriteableRegistry,
                threadPool,
                settingsModule.getIndexScopedSettings(),
                circuitBreakerService,
                bigArrays,
                scriptService,
                clusterService,
                client,
                metaStateService,
                engineFactoryProviders,