new feature: support configuration alias

### Feature Description

Allow different config keys to mean the same thing so that users can more easily migrate from other system to OpenDAL. For example, `aws_access_key_id` and `access_key_id` can just be aliases to each other and configure the same access key ID of S3 client.

### Problem and Solution

We are considering using OpenDAL as a replacement for the Arrow object_store. Currently this require a migration because the config keys are different, for example if the user set `aws_access_key_id` in object_store, we need to ask users to rename it to `access_key_id`, or we need to do some internal translation for the users.

The internal translation approach definitely can work, but I think it would be nice to support configuration alias so users can more easily migrate in similar situations.

Let me know if this is something we are interested in supporting, or if we think this should be handled fully from an external integration.

### Additional Context

Arrow object_store currently already does something similar: https://github.com/apache/arrow-rs-object-store/blob/main/src/aws/builder.rs#L398-L440

### Are you willing to contribute to the development of this feature?

- [x] Yes, I am willing to contribute to the development of this feature.

Start by reading the issue and the referenced Arrow object_store AWS builder alias handling. Then inspect OpenDAL's configuration and service-builder entry points to determine where aliases would belong; done would mean defining and implementing a decided aliasing approach for keys such as aws_access_key_id and access_key_id, with migration behavior covered by tests.

Written by the indexing model from the issue text.