Add VTK output

[philbucher]

Hi,
I found your project useful for some tests of mine, thanks for making it available!
Postprocessing with paraview is sth that I like to do, so I decided to implement it

Please let me know if this is a contribution you are interested in. I can of course also make it optional, via feature or input argument.

Attached is the example in vtk-files so that you can take a look
Thanks!
vtk_output.zip

[philbucher]

@cmccomb

[cmccomb]

Thanks for opening this PR @philbucher! I should be able to look into the failed check in the next few days but please feel free to act on it before I do.

What do you think about adding a test for VTK output? It would also be great to have a usage example for cookbook.rs and examples/!

[philbucher]

I should be able to look into the failed check in the next few days but please feel free to act on it before I do.

I think the tokio::Runtime is outdated, does not seem to be related to my changes

What do you think about adding a test for VTK output? It would also be great to have a usage example for cookbook.rs and examples/!

sure that makes sense. I will have a look after the holidays. I can most probably also update the tokio failures, if you havent done it already

[cmccomb]

Sorry to assume that the test fail had something to do with your PR! I fixed the tokio issue.