Add application icon to new GUI

[eeintech]

Unfortunately Flet does not support it at the moment during run-time:

• UI: Display app icon and title instead of flet tuttle-dev/tuttle#168
• Cannot override built-in flet icon in title bar when running application (Windows) -- no packaging flet-dev/flet#991

Therefore building using Poetry and distributing Ki-nTree via PyPI will show the default application icon, examples:

The only way to add an icon is to require the user to build the app locally and package it with the flet pack command and --icon option: https://flet.dev/docs/guides/python/packaging-desktop-app#customizing-package-icon
It might be added to Poetry's pyproject.toml file with something like:

[tool.poetry.scripts]
kintree_build = flet pack --icon ...

This still feels very like a lot of work for just getting the proper icon!

[eeintech]

I've tried it and unfortunately PyInstaller does not support icons on Linux:

WARNING: Ignoring icon; supported only on Windows and macOS!

What a disappointment 😞

Reproduce

1. Add PyInstaller to Poetry (version ^5.8.0) dependencies list
2. Add script entry: kintree_build = 'kintree.build_app:build'
3. Create new file named build_app.py in kintree folder with the following content:

import os

def build():
    os.system('flet pack kintree_gui.py --icon logo.png')

if __name__ == '__main__':
    build()

[eeintech]

Won't make it into 1.0.0 as there is no support for this feature in Flet yet.