[Bug] Overlay multi monitor issue

[SaifAqqad]

Currently, when using multiple monitors, the overlay stores its position relative to the leftmost monitor's top left corner
which is not ideal because disconnecting one of the monitors may result in the overlay disappearing as it's placed out of the monitor's bounds.

[SaifAqqad]

This is fixed by commit 65deead

The overlay's relative position (as a percentage of the display resolution) is now used instead of the actual position, also multiple positions are now stored for each monitor, this allows the overlay to switch to different positions based on the connected displays.