added option to write metadata to hdf5 file

[shimwell]

Description

While chatting with @RemDelaporteMathurin this issue where it would be useful to know information on the nuclear data surfaced again as part of the LIBRA project

This PR would allow additional strings to be added to the hdf5 file when exporting it to hdf5, so we could add things like FENDL 3.2c or made with openmc version 0.15.0

Fixes # (issue)
issue

Checklist

• I have performed a self-review of my own code
• 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)