Remove meshes not used in regression tests

[psakievich]

I did a scan of the meshes we are not using for regression tests in the exawind-driver or nalu-wind. It is the majority of the repo. I'd like to give people a few days to comment and weigh in on if we should be keeping any of these, or if we should have tests using these meshes that are not there.

Our mesh repo is really a bottle neck for cloning and other issues though because it is so big. I would suggest that if we want a repo of meshes for historical purposes or verification tests we fork this one prior to this commit and don't submodule it in our codes. I'd like to keep the one paired to the actual codes as slim as possible.

Using du -shc this PR alone drops the mesh repo size from 1GB to 519MB

[ashesh2512]

If they aren’t used, I don’t see a reason to carry them around.

[marchdf]

Same. Great idea.

[jrood-nrel]

Thanks for doing this. To actually shrink the repo we will have to purge the history. It will screw up the submodule in Nalu-Wind and Exawind, but hopefully the fix is to just update the submodule to the single commit in this repo.

[psakievich]

Going to merge now, but we will wait until next week to purge the git history.