`sol_to_vtu_direct` fails to create VTUs if the output directory does not exist

[Alex-Vasile]

sol_to_vtu_direct is meant to take a .sol folder (e.g. "X_sol/") and convert it to VTUs producing a X_transient.pvd and a X_vtu/ folder. It will currently fail to create any VTUs if the x_vtu/ folder does not exist before hand.

It should instead create that folder itself on run if it doesn't exist.

[nasserma]

This seems like a bigger issue, there are utility functions that not documented and easily accessible for users, including this conversion utility function.

Suggestions for how to fix this issue?

[Alex-Vasile]

This seems like a bigger issue, there are utility functions that not documented and easily accessible for users, including this conversion utility function.

Suggestions for how to fix this issue?

I will handle the documentation, accessibility, and folder issue for this conversion function in a PR to close this issue.

Any of the other conversion/utility functions should get individual separate issues to make them easier to track and split the work.