`spec_plot` and `plot_spec` functions in acoustic_utils very confusing

Currently, `acoustic_utils` has a `spec_plot` and a `plot_spec` functions which is very confusing. 

`spec_plot` is using `librosa.display.specshow`, that can be just `plot_spec` since it is just `matplotlib`

`plot_spec` is using `plotly` so possibly rename to plot_spec_plotly