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
public static final LicensedFeature.Momentary AUTHORIZATION_ENGINE_FEATURE = LicensedFeature.momentary(
        null,
        "security-authorization-engine",
        License.OperationMode.PLATINUM
    );
    
    public static final LicensedFeature.Persistent CUSTOM_ROLE_PROVIDERS_FEATURE = LicensedFeature.persistent(
        null,
        "security-roles-provider",
        License.OperationMode.PLATINUM
    );
    public static final LicensedFeature.Momentary OPERATOR_PRIVILEGES_FEATURE = LicensedFeature.momentary(
        null,
        "operator-privileges",
        License.OperationMode.ENTERPRISE
    );
    public static final LicensedFeature.Momentary USER_PROFILE_COLLABORATION_FEATURE = LicensedFeature.momentary(
        null,
        "user-profile-collaboration",
        License.OperationMode.STANDARD
    );
    private static final Logger logger = LogManager.getLogger(Security.class);
    private final Settings settings;
    private final boolean enabled;
    private final SecuritySystemIndices systemIndices;
    private final ListenableFuture<Void> nodeStartedListenable;
    /* what a PITA that we need an extra indirection to initialize this. Yet, once we got rid of guice we can thing about how
     * to fix this or make it simpler. Today we need several service that are created in createComponents but we need to register
     * an instance of TransportInterceptor way earlier before createComponents is called. */
    private final SetOnce<TransportInterceptor> securityInterceptor = new SetOnce<>();