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
final AuditTrailService auditTrailService = new AuditTrailService(auditTrails, getLicenseState());
        components.add(auditTrailService);
        this.auditTrailService.set(auditTrailService);
        final TokenService tokenService = new TokenService(
            settings,
            Clock.systemUTC(),
            client,
            getLicenseState(),
            securityContext.get(),
            systemIndices.getMainIndexManager(),
            systemIndices.getTokenIndexManager(),
            clusterService
        );
        this.tokenService.set(tokenService);
        components.add(tokenService);
        
        final NativeUsersStore nativeUsersStore = new NativeUsersStore(settings, client, systemIndices.getMainIndexManager());
        final NativeRoleMappingStore nativeRoleMappingStore = new NativeRoleMappingStore(
            settings,
            client,
            systemIndices.getMainIndexManager(),
            scriptService
        );
        final AnonymousUser anonymousUser = new AnonymousUser(settings);
        components.add(anonymousUser);
        final ReservedRealm reservedRealm = new ReservedRealm(environment, settings, nativeUsersStore, anonymousUser, threadPool);
        final SecurityExtension.SecurityComponents extensionComponents = new ExtensionComponents(
            environment,
            client,
            clusterService,