Make ProductionTabs PaletteWidget columns and rows customisable

[OmegaBolt]

With a ClassicProductionQueue you can change the number of columns and rows with Columns, MinimumRows and MaximumRows on the ProductionPalette widget.

ProductionTabs PaletteWidget however completely ignores the *Rows tags and if Columns is set to anything but 3 all cameos disappear.

It would be great if they were read the same as they are for ClassicProductionQueues. Right now it doesnt seem like there's any control at all to the maximum number of cameos that'll be displayed at once, thus making it hard impossible to design a UI that doesnt have screen deep icon space.