Restructure plotting

[SebastianM-C]

We should decouple plotting from WGLMakie, so that plotting can also work with other backends.

We have some generic plotting functionality for plotting AbstractPICDataStructureswhich is on top of recipes (because we can't access the axes from recipes).

Options

• Transfer generic plotting functions to PICDataStructures. This might be the best option.
• Transfer generic plotting functions to SDFResults. Not ideal since we should split the generic plotting parts from the things that read from sdf files.
• Transfer generic plotting functions to PICAnalysisTools.