Added Hex code and RGB entries with automatic updates, improved code quality and performance

[UX0l0l]

Why?

I'm writing this pull request because I added some useful features that me (and my friend who is a professional graphic designer and animator) thought would be necessary in a widget like this by which inputting values and manipulating colors would become much easier compared to simply being left with a simple color wheel.

What does it do?

This pull request changes the script in such a way that allows the user to change the color value based on a hex code or RGB values due to the added hex and RGB entries and the way they update automatically to reflect the inputted color value (with the hex code the user has to press enter on his keyboard for the color to update, but the RGB values are automatically updated).

Conclusion

I believe this would be a great addition to the project and would introduce a helpful feature to all users of this python module.

SS after the edits:

Summary:

1. Added Hex code entry to be able to change hex code manually (updates on pressing enter)
2. Added RGB entry to be able to edit RGB values manually (updates on key press/release/automatically)
3. Cleaned up the code a bit
4. Additional perk: this could be easily implemented into CTkThemeMaker instead of the default tkinter askcolor (which is what I'm working on as well on this repo)

Any other suggestions or edits are welcome!