Add Learning Rate Schedulers

[Pale-Blue-Dot-97]

Is your feature request related to a problem? Please describe. No

Describe the solution you'd like Add support for constructing a scheduler from config parameters that is set as an attribute of MinervaModel just like optimisers. It's step method can then be called in like optimiser within modelio. The learning rate should also be stored in the logs, written to the writer and stored in any checkpointing so that the schedule can be resumed.

Describe alternatives you've considered None

Additional context None