This appears to be incompatible with pyinstaller. I get the following
when trying to run the executable generated with pyside6:
```
Traceback (most recent call last):
File "qt_ui\main.py", line 29, in <module>
File "PyInstaller\loader\pyimod03_importers.py", line 476, in exec_module
File "qt_ui\windows\QLiberationWindow.py", line 28, in <module>
File "PyInstaller\loader\pyimod03_importers.py", line 476, in exec_module
File "qt_ui\widgets\map\QLiberationMap.py", line 11, in <module>
ImportError: could not import module 'PySide6.QtPrintSupport'
```
* Move the UI code out of the plugin logic.
* Add types where needed.
* Move into game package.
* Improve error handling.
* Simplify settings behavior.
* Don't load disabled plugins.
* Remove knowledge of non-base plugins from game generation.
Fixes https://github.com/Khopa/dcs_liberation/issues/311