Document how Polaris works with different cloud storage(S3, Azure Blob Storage, GCS).

### Is your feature request related to a problem? Please describe.

The topic was briefly mentioned in https://polaris.apache.org/in-dev/unreleased/configuration/ and https://polaris.apache.org/in-dev/unreleased/overview/#storage-configuration. They don't provide enough clear instruction how Polaris service provider to set them. Having a dedicated page with more detailed information will be helpful.

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by reading the existing configuration and storage-configuration pages at polaris.apache.org/in-dev/unreleased/configuration/ and polaris.apache.org/in-dev/unreleased/overview/#storage-configuration. Document how Polaris is configured to work with S3, Azure Blob Storage, and GCS, with clearer provider setup instructions. Done means the dedicated page covers all three storage services without relying on the brief existing mentions.

Written by the indexing model from the issue text.