Make get_attribute/set_attribute a public method

### Describe the feature

Currently I can't explicitely access get_attribute or set_attribute, as its a private method.

### Use Case

In several use cases, for example when trying to integrate with CarrierWave, I have to write `instance_variable_get(:@data).get_attribute(column.to_sym)` which is obviously ugly

### Proposed Solution

Implement - similar to activerecord - to make get_attribute and set_attribute public methods.

### Other Information

_No response_

### Acknowledgements

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

### aws-sdk-ruby-record version used

latest

### Environment details (OS name and version, etc.)

latest