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 Map<String, Supplier<HttpServerTransport>> getHttpTransports(
        Settings settings,
        ThreadPool threadPool,
        BigArrays bigArrays,
        PageCacheRecycler pageCacheRecycler,
        CircuitBreakerService circuitBreakerService,
        NamedXContentRegistry xContentRegistry,
        NetworkService networkService,
        HttpServerTransport.Dispatcher dispatcher,
        ClusterSettings clusterSettings,
        Tracer tracer
    ) {
        if (enabled == false) { 
            return Collections.emptyMap();
        }
        Map<String, Supplier<HttpServerTransport>> httpTransports = new HashMap<>();
        httpTransports.put(
            SecurityField.NAME4,
            () -> new SecurityNetty4HttpServerTransport(
                settings,
                networkService,
                pageCacheRecycler,
                ipFilter.get(),
                getSslService(),
                threadPool,
                xContentRegistry,
                dispatcher,
                clusterSettings,