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/SecurityUsageTransportAction.java
} else {
            return Collections.emptyMap();
        }
    }
    static Map<String, Object> tokenServiceUsage(Settings settings) {
        return singletonMap("enabled", TOKEN_SERVICE_ENABLED_SETTING.get(settings));
    }
    static Map<String, Object> apiKeyServiceUsage(Settings settings) {
        return singletonMap("enabled", API_KEY_SERVICE_ENABLED_SETTING.get(settings));
    }
    static Map<String, Object> auditUsage(Settings settings) {
        Map<String, Object> map = Maps.newMapWithExpectedSize(2);
        map.put("enabled", XPackSettings.AUDIT_ENABLED.get(settings));
        if (XPackSettings.AUDIT_ENABLED.get(settings)) {
            
            map.put("outputs", Arrays.asList(LoggingAuditTrail.NAME));
        }
        return map;
    }
    static Map<String, Object> ipFilterUsage(@Nullable IPFilter ipFilter) {
        if (ipFilter == null) {
            return IPFilter.DISABLED_USAGE_STATS;
        }
        return ipFilter.usageStats();
    }
    static Map<String, Object> fips140Usage(Settings settings) {
        return singletonMap("enabled", FIPS_MODE_ENABLED.get(settings));
    }
}