eos.sp5 saving option added

[mari2895]

PR Summary

Jonah's changes to save eos.sp5 if needed

PR Checklist

• [ ] Adds a test for any bugs fixed. Adds tests for new features.
• [x] Format your changes by calling scripts/bash/format.sh.
• [x] Explain what you did.

[mari2895]

@Yurlungur Compiles, runs, and also compared lightbulb outcome (density) generated using eos.h5 and eos.sp5 and was the same.