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
components.add(nativeUsersStore);
        components.add(nativeRoleMappingStore);
        components.add(realms);
        components.add(reservedRealm);
        systemIndices.getMainIndexManager().addStateListener(nativeRoleMappingStore::onSecurityIndexStateChange);
        final CacheInvalidatorRegistry cacheInvalidatorRegistry = new CacheInvalidatorRegistry();
        cacheInvalidatorRegistry.registerAlias("service", Set.of("file_service_account_token", "index_service_account_token"));
        components.add(cacheInvalidatorRegistry);
        systemIndices.getMainIndexManager().addStateListener(cacheInvalidatorRegistry::onSecurityIndexStateChange);
        final NativePrivilegeStore privilegeStore = new NativePrivilegeStore(
            settings,
            client,
            systemIndices.getMainIndexManager(),
            cacheInvalidatorRegistry
        );
        components.add(privilegeStore);
        dlsBitsetCache.set(new DocumentSubsetBitsetCache(settings, threadPool));
        final FieldPermissionsCache fieldPermissionsCache = new FieldPermissionsCache(settings);
        final FileRolesStore fileRolesStore = new FileRolesStore(
            settings,
            environment,
            resourceWatcherService,
            getLicenseState(),
            xContentRegistry
        );
        final NativeRolesStore nativeRolesStore = new NativeRolesStore(
            settings,
            client,
            getLicenseState(),
            systemIndices.getMainIndexManager()