Remove gsl dependency

[aprilnovak]

Reason

After openmc-dev/openmc#3225 is merged (Thanks @gridley!), let's remove the GSL dependency in Cardinal. It's tiny, and only adds headaches to user builds (actually non-negligible number of problems for users hitting system gsl libraries instead of the OpenMC submodule, some examples).

Design

• Remove gsl from civet_recipes
• Replace the very small amount of gsl within Cardinal with equivalents

Impact

Better user experience.