lightning: log params

[dberenbaum]

Adds lightning param logging, which requires user setup like:

class MyLightningModule(LightningModule):
    def __init__(self, myparam):
        self.save_hyperparameters()

This is the lightning way 🤷 (see https://forums.pytorchlightning.ai/t/how-to-save-hparams-when-not-provided-as-argument-apparently-assigning-to-hparams-is-not-recomended/339/3)