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
REALMS_FEATURE_FAMILY,
        "saml",
        License.OperationMode.PLATINUM
    );
    public static final LicensedFeature.Persistent OIDC_REALM_FEATURE = LicensedFeature.persistent(
        REALMS_FEATURE_FAMILY,
        "oidc",
        License.OperationMode.PLATINUM
    );
    public static final LicensedFeature.Persistent JWT_REALM_FEATURE = LicensedFeature.persistent(
        REALMS_FEATURE_FAMILY,
        "jwt",
        License.OperationMode.PLATINUM
    );
    public static final LicensedFeature.Persistent KERBEROS_REALM_FEATURE = LicensedFeature.persistent(
        REALMS_FEATURE_FAMILY,
        "kerberos",
        License.OperationMode.PLATINUM
    );
    
    public static final LicensedFeature.Persistent CUSTOM_REALMS_FEATURE = LicensedFeature.persistent(
        REALMS_FEATURE_FAMILY,
        "custom",
        License.OperationMode.PLATINUM
    );
    public static final LicensedFeature.Momentary DELEGATED_AUTHORIZATION_FEATURE = LicensedFeature.momentary(
        null,
        "security-delegated-authorization",
        License.OperationMode.PLATINUM
    );