Moves my (sabirm)'s custom item to common loadout pool

Moves the white sundress to the common pool. Same cost as the regular sundress, 3 points. Also adds a sprite for it when it's on the ground/in the inventory.

As requested (by myself). I'm not sure how the other changes in item_defines.dm were made, but it doesn't look like it has actually changed anything. Just deleted some spaces automatically, I suppose.

You can comment out the common loadout addition, if you'd like, and will need to modify the parts I can't access.
Yeah that will do it too.

By renaming the paths it will make it so that vars on one will also be "inherited" by the other dress but it's not so essential here.