Folder: Fix icon positioning on screen/available geometry changes
These patches prevents icon position changes or desync with backend few times per day on panel resize, screen (dis)connection, PC suspend/resume, etc. I tested it by disconnecting screen, PC suspend/resume, relogin, plasmashell restart, screen resolution and scaling changes, panel resize - seems to work correctly now in most cases on my PC.
I'm reverting one commit, because it's incorrect - available geometry changed signal is comming before GridView resize, so perStripe is calculated to wrong width/height - it causes a lot of issues. Also it's not needed, because perStripe is automatically updated from GridView property binding when GridView resizes.
Also these patches preserves icon position when changing resolution to a non-existent resolution. It's preserving icons position only when plasmashell is running; if monitor resolution changes when plasmashell is not running - it's not working yet (it can be improved later).