All GUI should change color when hovered

[FormularSumo]

Currently buttons with images don't, and nor do cards in deck editor.

Buttons should be pretty easy to do, for example recolour images if no text (as in this case they're normally solid white/black, if not could be a background instead).Alternatively could add another parameter for if image is background/wants recolouring.

Cards in deck editor this doesn't work so well, perhaps instead they could have a thin blue border similar to the red one they have when hovering over being deleted