[FEATURE REQUEST] Add stl support with visualisation

[fullcontrol-xyz]

Is your feature request related to a problem? Please describe.
stl-import will be described soon. It would be useful to have the ability to visualise the stl in addition to the current tool-path plot

Describe the solution you'd like
Ideally, use plotly, to avoid added extra dependencies

Describe alternatives you've considered
If the stl-manipulation package (e.g. trimesh) includes plotting capabilities, that may be an alternative, but not ideal since the plotly code would need to be reproduces for that package if the plot showed both the stl and the toolpath.

Additional context
We will need to support more than stl files. the chosen mesh handling library should allow that. As a minimum, the mesh handling library should allow planar slicing, but additional useful capabilities may be features to transform/scale a mesh and potentially smooth/fix-errors in meshes.

An article on mesh visualisation:

https://towardsdatascience.com/python-libraries-for-mesh-and-point-cloud-visualization-part-1-daa2af36de30

https://towardsdatascience.com/python-libraries-for-mesh-point-cloud-and-data-visualization-part-2-385f16188f0f