please don't delete AwsHostNameUtils

### Describe the feature

I've noticed that `AwsHostNameUtils` has a comment "TODO This isn't used for as many services as it supports. Can we simplify or remove it?".

It is used in the hadoop s3a client to work out the signing region of a bucket.

Removing it would break things and make people sad. 😢 (*)

Please leave, and ideally update the docs to say "this is used externally". Thanks.

(*) also it'd stop them dropping in updated SDK releases to hadoop installations and lead to bug reports on this project

### Use Case

`getS3RegionFromEndpoint()` to continue to return region endpoints.

### Proposed Solution

_No response_

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### AWS Java SDK version used

2.35.4

### JDK version used

8, 17

### Operating System and version

various