Coverage mode: add substractive option

As far as I understand, the "Coverage mode" works in an additive way. If I check `bar` + `restaurant` if will show me the places that at at least X min from one OR the other.

It would be useful to be able to switch that to an "AND", so if I check `bar` + `restaurant` it will show me the places that don't have both around.

The idea is to be able to select multiple criterias. For example `daycare+doctor+square/park", ideally when hovering on an area it could show me in the tooltip which selected criteria isn't around.