Develop `plot_model_timeseries()` for plotting transient model results

[lawrenceabird]

Some ISSM output is provided as 1D timeseries data (e.g. md.results.TransientSolution.IceVolume). Some ISSM output is provided as 2D timeseries data (e.g. md.results.TransientSolution.Vel).

Currently, 2D plots of individual timesteps can be plotted using plot_model_field(). No support exists for 1D output.

Requirements:

• Implement plot_model_timeseries_1d() for efficient plotting of 1D transient results.
• Implement plot_model_timeseries_2d() to generate GIF/animation of transient 2D output fields
• Implement plot_model_timeseries() as an efficient wrapper for these functions.