🔨 Major Rewrite: PyQt5 Conversion!

[savbell]

I've rewritten a large part of the codebase while updating how the settings are configured and converting to PyQt5 for the UI. Below are the major changes. Please open an issue if you encounter any problems with the new structure!

Added

• New settings window to configure WhisperWriter.
• New main window to either start the keyboard listener or open the settings window.
• New continuous recording mode (Issue #40).

Changed

• Migrated status window from using tkinter to PyQt5.
• Migrated from using JSON to using YAML to store configuration settings.

Removed

• No longer using keyboard package to listen for key presses.