Cleanup logic for clickable/selectable listItem elements

[MeoMix]

Currently there's a lot of weirdness going on in the CSS surrounding clickable/selectable elements.

This horrible selector exists because I thought all listItem's would want a :hover effect. It turns out that's not actually the case (or maybe those things shouldn't be considered listItems, I don't know.)

Regardless, this isn't working and it needs to be broken down and reworked.

&:not(.is-disabled):not(.grouping-item):not(.simpleListItem):hover {
    background: @dark--quinary;
}

Similarly, I've got this clickable class:

.listItem--clickable {
    cursor: pointer;
}

because I thought all list items would want to be clickable, but that's not always true, either. Sometimes I'm just presenting information in a nice way, but there's no other options available in the list item so no click effect.