refactor: Add Python type annotations wherever appropriate

[mikomikotaishi]

This pull request:

• Moves Colors and ColorFormatter to a separate file, rather than repeating it three times
• Adds Python type annotations wherever/whenever appropriate
• Organises import statements alphabetically, and adds from import statements wherever appropriate for name simplification
• Replaces string concatenations with fstrings when possible
• Replaces if/else with match

[kavishdevar]

did not expect to see any changes in the hearing aid code (i just made it to experiment), but thanks!