[Feature] Add OneHotEncoderTransformer

[ErikBavenstrand]

Is your feature request related to a problem? Please describe.
Currently, there is no built-in functionality to perform one-hot encoding on categorical data in the mleko library.

Describe the solution you'd like
I would like to add a OneHotEncoderTransformer to the library, which would allow users to easily perform one-hot encoding on their categorical data.

Describe alternatives you've considered
An alternative could be to use pandas' get_dummies function or sklearn's OneHotEncoder, but having a built-in transformer in the mleko library would make the process more streamlined and consistent.

Additional context
One-hot encoding is a common preprocessing step in machine learning pipelines, so this feature would be a valuable addition to the mleko library.