This is the version for Plasma 6.
Because I don’t really like my implementation of the version for plasma 5 and its limitation of 10 lines, so I decided to completely redo it. But, because I'm far from normal programming, I took the amazing USwitch widget as a basis https://store.kde.org/p/2135898 and remade it to suit my needs.
Special thanks to the author of the original USwitch widget!
* adding installed applications to the menu
* enable/disable session/power button
There is a minor bug. When adding a widget and setting it up, the dimensions are saved without problems. However, after a reboot, if you delete the menu item, the widget's dimensions will remain the same. You will have to delete it again and place it on the panel.