allow createing essential clusters on AWS

[zhangyangyu]

No description provided.

[Copilot]

Pull Request Overview

This PR updates the TiDB Cloud API from "Serverless" to "Starter and Essential", expanding support to allow creating essential clusters on AWS. The changes reflect a rebranding and expansion of the API to support both Starter (formerly Serverless) and Essential cluster types.

Key changes include:

• API documentation updates to reflect new naming and support for both cluster types
• Removal of cloud storage related models (S3, GCS, OSS, Azure Blob storage configurations)
• Simplification of audit log configuration by removing cloud storage options
• Updates to model structures for partial cluster updates

Reviewed Changes

Copilot reviewed 87 out of 87 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
utils.go, response.go, model_v1beta1_region_cloud_provider.go	Updated API documentation header comments from "Serverless" to "Starter and Essential"
model_v1beta1_partial_update_cluster_request_partial_update_cluster.go	Updated struct comments to be more descriptive and user-friendly
model_v1beta1_cluster_service_partial_update_cluster_body*.go	Added new model files for partial cluster updates with simplified structure
model_v1beta1_cluster__cloud_storage.go	Removed cloud storage models (S3, GCS, OSS, Azure Blob)
model_v1beta1_cluster_audit_log_config.go	Simplified audit log config by removing cloud storage and rotation options
model_v1beta1_cluster_auto_scaling.go, model_v1beta1_cluster_automated_backup_policy.go	Updated field documentation to be more descriptive

Comments suppressed due to low confidence (1)

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