Make axis labels created by `PlotDataXD` objects more flexible

Right now, axis labels for plotting with Plots.jl are automatically determined to be `x`, `y`, or `z` (see `_get_dimensions` and `_get_guides` in `src/visualization/plot_recipes.jl`). This precludes using `PlotData1D` from using it conveniently for something like `TimeSeriesCallback` results.

A possible approach would be to store the axis labels with the `PlotDataXD` objects depending on from which data source they were created, instead of determining the labels on the fly at plot time.

Read _get_dimensions and _get_guides in src/visualization/plot_recipes.jl, then trace how PlotData1D and other PlotDataXD objects are created from data sources. Define how axis labels should be retained by those objects so TimeSeriesCallback results can use meaningful labels instead of x, y, or z. Done means plotting uses the stored source-specific labels.

Written by the indexing model from the issue text.