Add SDK access to the parameters available for NSS

Is your feature request related to a problem?

It's currently challenging to get documentation for available parameters on the with_train, with_generate, etc. methods of SafeSynthesizer. While this is all documented in https://nvidia-nemo.github.io/Safe-Synthesizer/latest/reference/nemo_safe_synthesizer/config/training/ and similar locations, it would be more agent friendly to also provide a way to access this in the SDK.

This is separate than the CLI which already provides safe-synthesizer --help.

Describe the solution you'd like

Variety of options are possible. A SafeSynthesizer.help() method may be easiest, though need to generate that string somehow, hopefully automated.

Providing a meaningful docstring for the individual methods is another option, so help(builder.with_train) actually tells you the parameters that are available.

Describe alternatives you've considered

No response

Additional context

No response

Start by reading the SafeSynthesizer SDK methods named in the issue, especially with_train and with_generate, and compare their parameter documentation with the existing CLI help from safe-synthesizer --help. Decide how the SDK should expose the available parameters and verify that the resulting help or docstrings cover the documented training and generation options.