Provide helper function for SDK client name with different naming style (e.g. snake case)

### Clear and concise description of the problem

When generate SDK from swagger, modelerfour depends on [@azure-tools/codegen](https://github.com/Azure/autorest/tree/main/packages/libs/codegen) to provides [some helper function about naming](https://github.com/Azure/autorest/blob/fa08f8cc5047c03320be8928d7f62d9235238f0a/packages/libs/codegen/src/formatter/formatter.ts#L102-L132) for different style. Typespec doesn't have similar helper function so Python emitter planned to adopt `@azure-tools/codegen` so that there is no naming breakings when migrate from Swagger to Typespec in the future. However, confirmed with @timotheeguerin that `@azure-tools/codegen` is not maintained anymore so it will be very helpful if Typespec could provide similar helper function

### Checklist

- [X] Follow our [Code of Conduct](https://github.com/microsoft/typespec/blob/main/CODE_OF_CONDUCT.md)
- [X] Read the [docs](https://typespec.io/docs/).
- [X] Check that there isn't already an issue that request the same feature to avoid creating a duplicate.