make uwuw optional

[LukeLabrie]

Description

This PR allows for OpenMC to be configured with a version of DAGMC that was built without UWUW (University of Wisconsin Unified Workflow). This was useful for me in order to bypass the PyNE dependency.

Currently I've just added a new cmake variable, and separated out the uwuw-related methods in dagmc.cpp so they can be handled accordingly by the preprocessor.

Checklist

• [x] I have performed a self-review of my own code
• [x] I have run clang-format (version 15) on any C++ source files (if applicable)
• [ ] I have followed the style guidelines for Python source files (if applicable)
• [ ] I have made corresponding changes to the documentation (if applicable)
• [ ] I have added tests that prove my fix is effective or that my feature works (if applicable)

[shimwell]

Wow this is an interesting PR. Do you happen to have any info on the time saved when compiling openmc without UWUW or the reduction in memory footprint of the resulting executable.

I would be keen to follow up this PR and add without UWUW as an option to the conda package as well. I'm thinking this might make resolving conda environments easier as I still have trouble installing openmc, cadquery, moab and gmsh in a single environment.

[LukeLabrie]

@shimwell, so it saves me about a minute of compile time on DAGMC (single-thread), but does not appreciably change the compile time for openmc.

the executable is only ~2kb smaller for me

[gridley]

Nice. Not sure if intentional, but it always reminded me of this:

https://en.wikipedia.org/wiki/Uwu