Add method which returns the pyvista plotter

[roosre]

Description of the feature

There are several methods available to plot a field but the user cannot further tune the plot. Methods which return the pyvista plotter instead of showing the plot resolves this limitation.

The is feature requests origins from the need to hide all elements without results. The elements of interest are barely visible in this plot (example ishere).
nan_opacity does not really help because then only the element faces become visible.

Steps for implementing the feature

No response

Useful links and references

Look at methods such as plot_contour and extract the generation of the plot from showing it. An option could also be to add a function argument whether to show the plot or return the plotter.