1026 logical source parser

[subagonsouth]

Change Summary

Overview

• Added function to parse logical source into components
• Added function to parse sensor number from string

Updated Files

• imap_processing/hi/l1b/hi_l1b.py
  • Use new parser function
• imap_processing/hi/l1c/hi_l1c.py
  • Use new parser function
• imap_processing/hi/utils.py
  • Add utility function for parsing filename like strings such as logical source
  • Add function for parsing integer sensor number from string
• imap_processing/tests/hi/test_utils.py
  • Add test coverage for two new functions

Closes: #1026