Create a hover state that hold the current raid card in place

[NthMetal]

Sometimes raids go too fast. So it might be nice to have a hover state where the raid card is kept in a fixed position while hovered (with a similarly sized gap in the column) so that it's easier to click a specific raid.

That code is probably going to affect the html here: https://github.com/NthMetal/gbraidfinder/blob/master/front/src/app/app.component.html#L70

Angular cdk overlay may also be useful: https://material.angular.io/cdk/overlay/overview