Add Alt behavior for skills linked to mines/traps

This has been brought up in a couple threads over the years, but I would like to suggest it again, given the new "Detonate Mines is triggered while you are moving" mastery, which makes mines feel so much better on console.

Currently, all Trap and Mine skills have an Alt behavior of allowing you to drop them at your feet. However, when another skill is linked to trap/blastchain/high impact support, there is no option to select this behavior. As a result, they are locked to the default behavior, which isn't useful for a lot of gameplay. More often than not, I would prefer to have mines drop at the characters feet while moving, instead of max distance.