Support Creating a Single Tenant Occupying All Resources

Description

We are using OceanBase as a Raft-based MySQL cluster and have only created a single "obmysql" tenant. This tenant is expected to occupy all available resources (CPU, memory, etc.) in the obcluster. Currently, ob-operator does not support the direct creation of a tenant with such configurations. Additionally, when the cluster is expanded (e.g., via CPU or memory scaling), the tenant should automatically scale to occupy the newly available resources. We would like to request a feature that allows ob-operator to create a single tenant that utilizes all available resources in the cluster by default and automatically scales when the cluster is expanded.

Requirements: ob-operator should provide a configuration to create a single tenant that automatically occupies all available resources (CPU, memory, etc.) of the OceanBase cluster.

Auto-scaling with cluster expansion: When the cluster is expanded, increasing available resources (CPU or memory), the tenant should automatically scale to occupy the newly available resources without requiring manual intervention.

We appreciate your consideration of this feature request.

No files, tests, or entry points are named in the issue. Start by tracing how ob-operator creates and updates OceanBase tenants and how cluster CPU or memory expansion is reconciled; done means a single-tenant configuration consumes all available resources initially and automatically adjusts after expansion.