IfW: add VTK output of slice in XY to driver

[andrew-platt]

This PR is ready to merge.

NOTE: this is a duplicate of #1643 which was automatically closed when the dev-unstable-pointers branch was deleted. See discussions on that PR.

Feature or improvement description This allows visualizing a slice through hub-height (or other height) when comparing with a simulation. The user can specify the height at which to export the slice. At the moment it is a very slow process due to the looping and because it exports over the entire time range (this could be improved later).

This figure shows the XY plane at the hub height for a Mann wind field (HAWC format). The vertical plane is exported from the driver using the WrVTK option. Both are taken at 23.625 seconds.

Related issue, if one exists #1643

Impacted areas of the software InflowWind driver only

Additional supporting information During testing of the wake added turbulence feature, I ran into issues in verifying that the background turbulence was being added correctly. To check this, I needed some way to visualize the XY plane through the hub from the Mann box turbulence.

Test results, if applicable No test cases are affected. I did not add a test case for this since it is a very slow code to execute.

[andrew-platt]

• [ ] Verify all suggested changes from #1643 have been implemented.