Integrate customtkinter (or QT?)

[Lenochxd]

Attempt to integrate customtkinter

• Tried to replace tkinter with customtkinter for better UI consistency, dark theme support, and better Linux support.
• Encountered several issues:
  • Opening the QR code window again while it's already open results in a GIL error (yeah). Tried to solve this problem using threads, and it works but makes the function slower and laggy the more often we use it.
  • The port input box can crash the QR code window if the QR code window is opened without closing the port input box.
  • System light/dark mode is inconsistent for the port input box.
  • Other potential issues may exist.
• This branch was made for contributors, be aware of these issues when working with this branch.