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
return docId.substring(DOC_ID_PREFIX.length());
    }
    static ProfileDocument buildProfileDocument(BytesReference source) throws IOException {
        if (source == null) {
            throw new IllegalStateException("profile document did not have source but source should have been fetched");
        }
        try (XContentParser parser = XContentHelper.createParser(XContentParserConfiguration.EMPTY, source, XContentType.JSON)) {
            return ProfileDocument.fromXContent(parser);
        }
    }
    private static XContentBuilder wrapProfileDocument(ProfileDocument profileDocument) throws IOException {
        final XContentBuilder builder = XContentFactory.jsonBuilder();
        builder.startObject();
        builder.field("user_profile", profileDocument);
        builder.endObject();
        return builder;
    }
    private static XContentBuilder wrapProfileDocumentWithoutApplicationData(ProfileDocument profileDocument) throws IOException {
        final XContentBuilder builder = XContentFactory.jsonBuilder();
        builder.startObject();
        builder.field(
            "user_profile",
            profileDocument,
            
            new ToXContent.MapParams(Map.of("include_labels", Boolean.FALSE.toString(), "include_data", Boolean.FALSE.toString()))
        );
        builder.endObject();
        return builder;
    }
    /**