Managing plot style #174
Description
The plot style management for the pre-defined plots in FOOOF is not as flexible as it could be. I think we now have a better approach for doing this in NDSP that could be used as a model to update some of this management in FOOOF. I think things are already similar enough to do this in FOOOF without any breaking changes, in a way that mimics what was updated in NDSP in neurodsp-tools/neurodsp#185
Note: this issue came up in part with discussions with @tyfarnan on work with custom plots.