chore: code logic separation and clean up

[tartarughina]

Improving the repo code readability and maintainability by:

• Dividing the code into logic blocks.
  • Before, the bulk of the code was under java.rs. Now that code has been aggregated into specific files
• Deduplicate code into reusable functions
  • General code that can be used by multiple files has been grouped into a single util.rs file

Feature:

• Add ~ expansion for Unix-like systems under util.rs

[playdohface]

Nice, this works for me. At this point I'm wondering if we even need the chatty comments anymore, but they are somewhat charming. But clippy has a bunch of helpful things to say still, we might want to incorporate that