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
new FixedExecutorBuilder(
                    settings,
                    SECURITY_CRYPTO_THREAD_POOL_NAME,
                    (allocatedProcessors + 1) / 2,
                    1000,
                    "xpack.security.crypto.thread_pool",
                    false
                )
            );
        }
        return Collections.emptyList();
    }
    @Override
    public UnaryOperator<Map<String, IndexTemplateMetadata>> getIndexTemplateMetadataUpgrader() {
        return templates -> {
            
            templates.remove("security_audit_log");
            
            templates.remove("security-index-template");
            return templates;
        };
    }
    @Override
    public Function<String, Predicate<String>> getFieldFilter() {
        if (enabled) {
            return index -> {
                XPackLicenseState licenseState = getLicenseState();
                IndicesAccessControl indicesAccessControl = threadContext.get()
                    .getTransient(AuthorizationServiceField.INDICES_PERMISSIONS_KEY);
                if (indicesAccessControl == null) {