[ResponseOps] use Data Streams for AAD indices in serverless

resolves elastic#154266

Changes the way the alerts-as-data (AAD) indices are created and
written to, to allow them to be built as they have been in the past
(alias and backing indices created manually) OR as an ES Data Stream.

Serverless will use Data Streams, other environments will use the
existing alias and backing indices.  The determination is made by
optionally including the `serverless` plugin, and determining if it's
available.

x-pack/plugins/alerting/kibana.jsonc

@@ -30,7 +30,8 @@
       "usageCollection",
       "security",
       "monitoringCollection",
-      "spaces"
+      "spaces",
+      "serverless",
     ],
     "extraPublicDirs": [
       "common",

x-pack/plugins/alerting/server/alerts_service/alerts_service.ts

@@ -20,6 +20,7 @@ import {
   getIndexTemplateAndPattern,
 } from './resource_installer_utils';
 import { AlertInstanceContext, AlertInstanceState, IRuleTypeAlerts, RuleAlertData } from '../types';
+import { DataStreamAdapter } from './lib/data_stream_adapter';
 import {
   createResourceInstallationHelper,
   errorResult,
@@ -49,6 +50,7 @@ interface AlertsServiceParams {
   kibanaVersion: string;
   elasticsearchClientPromise: Promise<ElasticsearchClient>;
   timeoutMs?: number;
+  dataStreamAdapter: DataStreamAdapter;
 }
 
 export interface CreateAlertsClientParams extends LegacyAlertsClientParams {
@@ -114,10 +116,13 @@ export class AlertsService implements IAlertsService {
   private resourceInitializationHelper: ResourceInstallationHelper;
   private registeredContexts: Map<string, IRuleTypeAlerts> = new Map();
   private commonInitPromise: Promise<InitializationPromise>;
+  private dataStreamAdapter: DataStreamAdapter;
 
   constructor(private readonly options: AlertsServiceParams) {
     this.initialized = false;
 
+    this.dataStreamAdapter = options.dataStreamAdapter;
+
     // Kick off initialization of common assets and save the promise
     this.commonInitPromise = this.initializeCommon(this.options.timeoutMs);
 
@@ -296,6 +301,7 @@ export class AlertsService implements IAlertsService {
             esClient,
             name: DEFAULT_ALERTS_ILM_POLICY_NAME,
             policy: DEFAULT_ALERTS_ILM_POLICY,
+            dataStreamAdapter: this.dataStreamAdapter,
           }),
         () =>
           createOrUpdateComponentTemplate({
@@ -421,6 +427,7 @@ export class AlertsService implements IAlertsService {
             kibanaVersion: this.options.kibanaVersion,
             namespace,
             totalFieldsLimit: TOTAL_FIELDS_LIMIT,
+            dataStreamAdapter: this.dataStreamAdapter,
           }),
         }),
       async () =>
@@ -429,6 +436,7 @@ export class AlertsService implements IAlertsService {
           esClient,
           totalFieldsLimit: TOTAL_FIELDS_LIMIT,
           indexPatterns: indexTemplateAndPattern,
+          dataStreamAdapter: this.dataStreamAdapter,
         }),
     ]);