Fixed length char array results in malformed path string for WMM.COF file

[patkenneally]

Describe the bug
The fileName local variable in MagneticFieldWMM::initializeWmm is a fixed length char array. When basilisk is located in a folder tree depth whith a path string length of great than the fixed 100 characters, the module fails to find the WMM.COF because the path is malformed (cut off).

To Reproduce
Steps to reproduce the behavior:

1. Install basilisk in a directory structure where the path to the WMM.COF file is more than 100 characters in length.
2. Build and run all tests and those using MagneticFieldWMM will fail.

Expected behavior
The module to find WMM.COF regardless of location of basilisk on the OS. Tests to pass

Desktop (please complete the following information):

• OS: Macos
• Version 12.6.1
• Python version 3.9.15

Additional context
I realize that any solution might not sufficiently account for the OS limits on path length. That's a much deeper and more nuanced topic.