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/qa/profile/src/javaRestTest/java/org/elasticsearch/xpack/security/profile/ProfileIT.java
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.IntStream;
import static org.hamcrest.Matchers.anEmptyMap;
import static org.hamcrest.Matchers.contains;
import static org.hamcrest.Matchers.containsInAnyOrder;
import static org.hamcrest.Matchers.empty;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThan;
import static org.hamcrest.Matchers.hasKey;
import static org.hamcrest.Matchers.hasSize;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.nullValue;
public class ProfileIT extends ESRestTestCase {
    public static final String SAMPLE_PROFILE_DOCUMENT_TEMPLATE = """
        {
          "user_profile": {
            "uid": "%s",
            "enabled": true,
            "user": {
              "username": "%s",
              "roles": [
                "role1",
                "role2"
              ],
              "realm": {
                "name": "realm_name_1",