As we are rolling out the user profile feature, we'd like to expand the [Usage API](https://www.elastic.co/guide/en/elasticsearch/reference/current/usage-api.html) to report usage stats of user profiles such as (1) number of enabled user profiles and (2) number of user profiles that are [activated](https://www.elastic.co/guide/en/elasticsearch/reference/current/security-api-activate-user-profile.html) over the past X days. 

Response of the Usage API already contains a `security` field that groups relevant stats from security related features. We expect the new stats for user profiles should be added under it as well, for example:
```
{
  "security: {
    "user_profile": {
      "activated": 78,
      "recently_activated": 42  <1>
    }
  }
}
```
<1> The use of `recently_` is chosen to avoid the field to be tied to a specific time period so it is easier to evolve the definition in future.

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/Security.java
@Override
    public void onIndexModule(IndexModule module) {
        if (enabled) {
            assert getLicenseState() != null;
            if (XPackSettings.DLS_FLS_ENABLED.get(settings)) {
                assert dlsBitsetCache.get() != null;
                module.setReaderWrapper(
                    indexService -> new SecurityIndexReaderWrapper(
                        shardId -> indexService.newSearchExecutionContext(
                            shardId.id(),
                            0,
                            
                            
                            null,
                            () -> {
                                throw new IllegalArgumentException("permission filters are not allowed to use the current timestamp");
                            },
                            null,
                            
                            emptyMap()
                        ),
                        dlsBitsetCache.get(),
                        securityContext.get(),
                        getLicenseState(),
                        indexService.getScriptService()
                    )
                );
                /*
                 * We need to forcefully overwrite the query cache implementation to use security's opt-out query cache implementation. This
                 * implementation disables the query cache if field level security is used for a particular request. We have to forcefully