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/profile/ProfileService.java
profileIndex.prepareIndexIfNeededThenExecute(
            listener::onFailure,
            () -> executeAsyncWithOrigin(
                client,
                getActionOrigin(),
                UpdateAction.INSTANCE,
                updateRequest,
                ActionListener.wrap(updateResponse -> {
                    assert updateResponse.getResult() == DocWriteResponse.Result.UPDATED
                        || updateResponse.getResult() == DocWriteResponse.Result.NOOP;
                    listener.onResponse(updateResponse);
                }, listener::onFailure)
            )
        );
    }
    private String getActionOrigin() {
        
        if (clusterService.state().nodes().getMinNodeVersion().onOrAfter(VERSION_SECURITY_PROFILE_ORIGIN)) {
            return SECURITY_PROFILE_ORIGIN;
        } else {
            return SECURITY_ORIGIN;
        }
    }
    private static String uidToDocId(String uid) {
        return DOC_ID_PREFIX + uid;
    }
    private static String docIdToUid(String docId) {
        if (docId == null || false == docId.startsWith(DOC_ID_PREFIX)) {
            throw new IllegalStateException("profile document ID [" + docId + "] has unexpected value");
        }