LilyPond figures and matplotlib

[YannickJadoul]

Following up on #66: how should the LilyPond-generated figures interact with matplotlib?

A couple of discussion points (partially taken from https://github.com/Jellevanderwerff/thebeat/pull/66#issuecomment-1872622440):

• I feel like the dpi argument is somewhat confusingly mixed between lilypond and matplotlib? Is there a point in generating a higher-resolution image from lilypond, but
• What's the reason for putting the lilypond-generated figure inside another matploblib figure? This also runs the risk of users saving the matplotlib plot of the previously-saved-and-read lilypond image?
• Moreover, if the idea is that the lilypond image could be plotted in the context of a larger plot, a user can currently not choose at which coordinates and on which scale to put the image in the larger plot?