Python package

[luisbocanegra]

• [x] Allow to install kde-material-you-colors as python package
• [x] Detect and terminate existing instances
• [x] Install desktop entries and allow to enable autostart
• [x] Install default config
• [x] Detect backend from ~/.local/bin, the regular install location of pip cli programs, when copying desktop entries & autostart

[luisbocanegra]

If someone can please test the uploaded package https://pypi.org/project/kde-material-you-colors/ Checking and terminating existing instances won't work as it relied in the script specific location, that will need to be changed for something else.