Shuffle over epochs: Cleanup definition

[voegtlel]

Right now, this is not most intuitive to combine shuffle_over_epochs(_multiplier) with epochized_blend:

• Shuffle over epochs will also repeat the dataset that many times (todo: implement to stop after singular dataset length, even if then not all samples may have been seen, but that is intended)
• Clean up the definition of what shuffle_over_epochs(_multiplier) = -1|None means, by introducing literals instead: Union[Literal["sample_without_replacement", "disable_shuffle"], int] where int>=1
• Don't allow combining disable_shuffle with a defined shuffle >1 (maybe set the default to unset?)
• Also allow floats, as for repetitions