feat(server): add cloud indexer with Elasticsearch and Manticoresearch providers (#11835)

close CLOUD-137

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Introduced advanced workspace-scoped search and aggregation capabilities with support for complex queries, highlights, and pagination.
  - Added pluggable search providers: Elasticsearch and Manticoresearch.
  - New GraphQL queries, schema types, and resolver support for search and aggregation.
  - Enhanced configuration options for search providers in self-hosted and cloud deployments.
  - Added Docker Compose services and environment variables for Elasticsearch and Manticoresearch.
  - Integrated indexer service into deployment and CI workflows.

- **Bug Fixes**
  - Improved error handling with new user-friendly error messages for search provider and indexer issues.

- **Documentation**
  - Updated configuration examples and environment variable references for indexer and search providers.

- **Tests**
  - Added extensive end-to-end and provider-specific tests covering indexing, searching, aggregation, deletion, and error cases.
  - Included snapshot tests and test fixtures for search providers.

- **Chores**
  - Updated deployment scripts, Helm charts, and Kubernetes manifests to include indexer-related environment variables and secrets.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/data/app.ts

@@ -1,12 +1,13 @@
 import { Module } from '@nestjs/common';
 
 import { FunctionalityModules } from '../app.module';
+import { IndexerModule } from '../plugins/indexer';
 import { CreateCommand, NameQuestion } from './commands/create';
 import { ImportConfigCommand } from './commands/import';
 import { RevertCommand, RunCommand } from './commands/run';
 
 @Module({
-  imports: FunctionalityModules,
+  imports: [...FunctionalityModules, IndexerModule],
   providers: [
     NameQuestion,
     CreateCommand,