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 -->

.github/helm/affine/values.yaml

@@ -21,6 +21,11 @@ global:
     username: ''
     password: ''
     database: 0
+  indexer:
+    provider: ''
+    endpoint: ''
+    username: ''
+    password: ''
   docService:
     name: 'affine-doc'
     port: 3020