Draft: Refactor icon positioner saving and loading

The icon positioner saving and loading is handled by QML, which makes it a bit difficult to work with the logic in positioner CPP files.

This change does the following:

• Skips saving on anything that is not user interaction
  • When sourceRows are changed and screen is off
  • applyPositions() which goes through the source and proxy items, moves them around, etc.
  • In both these cases we have m_skipSave variable that is just disabling saving when they're operating
• Moved the save and load of config to positioner.cpp
  • Easier debugging of the saving and loading functions
  • Still uses the JSON style of save/loading like the old one
    • Technically should be compatible with the old config, which was also JSON.
• Makes the whole positioner accessible from FolderView
  • This is to allow easy access to the load and save methods from positioner.cpp
• Various checks for checking if screen is enabled or not to avoid doing unnecessary work when screen is off

Alternative to !2603

BUG: 482875